Recording medium, recording device, reproduction device, recording method and reproduction method

ABSTRACT

The present invention allows the usability of a write-once recording medium to be enhanced. The write-once recording medium is provided with an ordinary recording/reproduction area, an alternate area, a first alternate-address management information area (DMA) and a second alternate-address management information area (TDMA). In addition, written/unwritten state indication information (a space bitmap) is also recorded. The second alternate-address management information area is an area allowing alternate-address management information recorded therein to be renewed by adding alternate-address management information thereto. In addition, the written/unwritten state indication information indicates whether or not data has been recorded in each data unit (cluster) on the recording medium. Thus, it is possible to correctly execute management of defects and properly implement renewal of data in the write-once recording medium.

TECHNICAL FIELD

The present invention relates to a recording medium such as an opticalrecording medium used particularly as write-once recording media as wellas relates to a recording apparatus, a recording method, a reproductionapparatus and a reproduction method, which are provided for therecording medium.

BACKGROUND ART

As a technology for recording and reproducing digital data, there isknown a data-recording technology for using optical disks includingmagneto-optical disks as recording media. Examples of the optical disksare a CD (Compact Disk), an MD (Mini-Disk) and a DVD (Digital VersatileDisk). The optical disk is the generic name of recording media, which isa metallic thin plate protected by plastic. When a laser beam isradiated to the optical disk, the optical disk emits a reflected signal,from which changes can be read out as changes representing informationrecorded on the disk.

The optical disks can be classified into a read-only category includinga CD, a CD-ROM and a DVD-ROM, which the user is already familiar with,and a writable category allowing data to be written therein as isgenerally known. The writable category includes an MD, a CD-R, a CD-RW,a DVD-R, a DVD-RW, a DVD+RW and a DVD-RAM. By adopting a magneto-opticalrecording method, a phase-change recording-method or a pigmented-coatchange recording-method for the writable category, data can be recordedonto a disk of this category. The pigmented-coat change recording-methodis also referred to as a write-once recording-method. Since thispigmented-coat change recording-method allows data recording once andinhibits renewal of data onto the disk, the disk is good for data-savingapplications or the like. On the other hand, the magneto-opticalrecording method and the phase-change recording-method are adopted in avariety of applications allowing renewal of data. The applicationsallowing renewal of data include mainly an application of recordingvarious kinds of content data including musical data, movies, games andapplication programs.

In addition, in recent years, a high-density optical disk called ablue-ray disc has been developed in an effort to produce the product ona very large scale.

Typically, data is recorded onto a high-density optical disk and readout from the disk under a condition requiring a combination of a laserwith a wavelength of 405 nm and an objective lens with an NA of 0.85 tobe reproduced. The laser required in this condition is the so-calledblue laser. With the optical disk having a track pitch of 0.32 μm, aline density of 0.12 μm/bit, a formatting efficiency of about 82% and adiameter of 12 cm, data of the amount of up to 23.3 GB (gigabytes) canbe recorded onto and reproduced from the disk in recording/reproductionunits, which are each a data block of 64 KB (kilobytes).

There are also two types of optical disk having such a high density,i.e., optical disks of a write-once type and optical disks of a writabletype.

In an operation to record data onto an optical disk allowing data to berecorded therein by adoption of the magneto-optical recording method,the pigmented-coat change recording-method or the phase-changerecording-method, guide means for tracking data tracks is required.Thus, a groove is created in advance to serve as a pregroove. The grooveor a land is used as a data track. A land is a member having a shaperesembling a section plateau between two adjacent grooves.

In addition, it is also necessary to record addresses so that data canbe recorded at a predetermined location indicated by an address as alocation on a data track. Such addresses are recorded on grooves bywobbling the grooves in some cases.

That is to say, a track for recording data is created in advance astypically a pregroove. In this case, addresses are recorded by wobblingthe side walls of the pregroove.

By recording addresses in this way, an address can be fetched fromwobbling information conveyed by a reflected light beam. Thus, data canbe recorded at a predetermined location and reproduced from apredetermined location without creating for example pit data showing anaddress or the like in advance on the track.

By adding addresses as a wobbling groove, it is not necessary todiscretely provide an address area or the like on tracks as an area forrecording typically pit data representing addresses. Since such anaddress area is not required, the capacity for storing actual data isincreased by a quantity proportional to the eliminated address area.

It is to be noted that absolute-time (address) information implementedby a groove wobbled as described above is called an ATIP (Absolute TimeIn Pregroove) or an ADIP (Address in Pregroove).

In addition, in the case of recording media usable as media forrecording these kinds of data or not as reproduction-only media, thereis known a technology for changing a data-recording location on the diskby providing an alternate area. That is to say, this technology is adefect management technology whereby an alternate recording-area isprovided so that, if a location improper for recording data exits on thedisk due to a defect such as an injury on the disk, the alternaterecording-area can be used as an area serving as a substitute for thedefective location to allow proper recording and reproduction operationsto be carried out properly.

The defect management technology is disclosed in documents includingJapanese Unexamined Patent Publication No. 2002-521786, and JapanesePatent Laid-open Nos. Sho 60-74020 and Hei 11-39801.

By the way, it is naturally impossible to record data into an alreadyrecorded area in a write-once optical recording medium, that is, an areain which data has been recorded before. Examples of the write-onceoptical recording medium are a CD-R, a DVD-R and a high-densityrecording medium, which function as a write-once disk.

Specifications of most file systems to be recorded on an opticalrecording medium are defined by assuming the use of the opticalrecording medium as a ROM-type disk or a RAM-type disk. The ROM-typedisk is a reproduction-only medium and the RAM-type disk is a writableoptical disk. Specifications of a file system for a write-once recordingmedium allowing data to be stored therein only once limit functions ofthe ordinary file system and include special functions.

The specifications of a file system for a write-once recording mediumare a reason why the file system does not become widely popular. On theother hand, a FAT file system capable of keeping up with a variety ofOSes of an information-processing apparatus and other file systemscannot be applied to write-once media as they are.

Write-once media is widely used typically in applications of preservingdata. If the write-once media can also be used for the FAT file systemby keeping the general specifications of the file system as they are,the usability of the write-once media can be further enhanced.

In order to allow a widely used file system such as the FAT file systemand a file system for RAMs or hard disks to be applied to write-oncemedia as it is, however, a function to write data into the same addressas that of existing data is required. That is to say, a capability ofrenewing data is required. Of course, one of characteristics of thewrite-once media is that data cannot be written onto the media for thesecond time. Thus, it is impossible to use a file system for such awritable recording medium as it is in the first place.

In addition, when the optical disk is mounted on a disk drive ordismounted from it, the recording face of the disk may be injured independence on the state in which the disk is kept in the drive and theway in which the disk is used. For this reason, the aforementionedtechnique of managing defects has been proposed. Of course, even thewrite-once media must be capable of coping with a defect caused by aninjury.

In addition, in the case of the conventional write-once optical disk,data is recorded in a state of being compacted sequentially in areasstarting from the inner side. To put it in detail, there is no spaceleft between an area already including recorded data and an area inwhich data is to be recorded next. This is because the conventional diskis developed with a ROM-type disk used as a base so that, if anunrecorded area exists, a reproduction operation cannot be carried out.Such a situation limits the freedom of a random-access operation carriedout on the write-once media.

In addition, for a disk drive or a recording/reproduction apparatus, anoperation requested by a host computer to write data at an addressspecified in the operation as an address in a write-once optical disk oran operation to read out data from such an address is a process of aheavy load.

From what is described above, contemporary write-once media or, inparticular, write-once media implemented by a high-density optical diskhaving a recording capacity of at least 20 GB like the aforementionedblue-ray disk, is required to meet the following requirements. Thewrite-once media shall be capable of renewing data and managing defectsby execution of proper management, improving the random accessibility,reducing the processing load borne by the recording/reproductionapparatus, keeping up with a general-purpose file system by thecapability of renewing data and maintaining compatibility with writableoptical disks as well as reproduction-only disks.

DISCLOSURE OF INVENTION

It is thus an object of the present invention addressing such asituation to improve usability of a write-once recording medium byallowing data stored on the write-once recording medium to be renewedand by executing proper management of defects.

A recording medium provided by the present invention has a write-oncearea allowing data to be recorded therein once and including a main dataarea as well as a management/control area for recordingmanagement/control information for recording data into the main dataarea and reproducing data from the main data area.

The main data area includes a regular recording/reproduction area whichdata is recorded into and reproduced from as well as an alternate areafor recording data due to a defect existing in the regularrecording/reproduction area or for recording data in a process to renewdata. On the other hand, the management/control area includes a firstalternate-address management information area for recording firstalternate-address management information for managing alternate-addressprocesses using the alternate area and a second alternate-addressmanagement information area for recording the alternate-addressmanagement information in an updateable state in an updating processprior to a finalization process. In addition, the main data area or themanagement/control area is used for recording written/unwritten stateindication information for each data unit of the main data area and eachdata unit of the management/control area as information indicatingwhether or not data has been written into the data unit.

On top of that, in accordance with the alternate-address process,alternate-address management information is additionally recorded in thesecond alternate-address management information area and informationindicating effective alternate-address management information is alsorecorded.

In addition, in accordance with a data-writing process, thewritten/unwritten state indication information is additionally recordedin the second alternate-address management information area andinformation indicating effective alternate-address managementinformation is also recorded.

As an alternative, a written/unwritten state indication information areafor recording the written/unwritten state indication information isprovided in the main data area, in accordance with a data-writingprocess, the written/unwritten state indication information isadditionally recorded in the written/unwritten state indicationinformation area and last written/unwritten state indication informationin the written/unwritten state indication information area is madeeffective.

In this case, a portion in an alternate area of the main data area isused as the written/unwritten state indication information area, andinformation is recorded to indicate that the portion of the alternatearea is used as the written/unwritten state indication information areaand, hence, cannot serve as an area used for the alternate-addressprocess.

A recording apparatus provided by the present invention is a recordingapparatus designed for the recording medium described above. Therecording apparatus has write means for writing data onto the recordingmedium, confirmation means for determining whether or not data has beenrecorded at an address related to a data-writing request to write datain the main data area on the basis of the written/unwritten stateindication information, determination means for determining whether ornot an alternate-address process using the alternate area as well as thesecond alternate-address management information area can be carried outand write control means.

The write control means controls the write means to write data at theaddress related to the data-writing request and updates thewritten/unwritten state indication information if the confirmation meansdetermines that data has not been recorded at the address related to thedata-writing request. However, the write control means controls thewrite means to write data related to the data-writing request in thealternate area as well as updates the alternate-address managementinformation and the written/unwritten state indication information ifthe confirmation means determines that data has been recorded at theaddress related to the data-writing request whereas the determinationmeans determines that the alternate-address process can be carried out.

In addition, the write control means also updates the alternate-addressmanagement information by additionally recording alternate-addressmanagement information in the second alternate-address managementinformation area of the recording medium and records informationindicating effective alternate-address management information.

On top of that, the write control means also updates thewritten/unwritten state indication information by additionally recordingwritten/unwritten state indication information in the secondalternate-address management information area of the recording mediumand records information indicating effective written/unwritten stateindication information.

As an alternative, the write control means updates the written/unwrittenstate indication information by additionally recording written/unwrittenstate indication information in the main data area of the recordingmedium.

In addition, the recording apparatus further has set means for settingan indicator as to whether or not data can be renewed on the basis ofinformation recorded on the recording medium as information indicatingthat the portion of the alternate area in the main data area of therecording medium is used as the written/unwritten state indicationinformation area and, hence, cannot serve as an area used for thealternate-address process and on the basis of the substance of datarecorded in the portion existing in the alternate area as thewritten/unwritten state indication information area in a configurationwherein the write control means uses the portion of the alternate areaas the written/unwritten state indication information area andadditionally records the written/unwritten state indication informationin the written/unwritten state indication information area.

A reproduction apparatus provided by the present invention is areproduction apparatus designed for the recording medium describedabove. The reproduction apparatus includes read means for reading outdata from the recording medium, first confirmation means for determiningwhether or not data has been recorded at an address related to a readrequest to read out data from the main data area on the basis of thewritten/unwritten state indication information, second confirmationmeans for determining whether or not the address related to the readrequest to read out data from the main data area is an addresscompleting an alternate-address process on the basis of thealternate-address management information and read control means.

The read control means controls the read means to read out data from theaddress related to the read request if the first confirmation meansdetermines that data has been recorded at the address related to theread request and the second confirmation means determines that theaddress related to the read request is not an address completing analternate-address process. However, the read control means controls theread means to read out data related to the read request from thealternate area on the basis of the alternate-address managementinformation if the first confirmation means determines that data hasbeen recorded at the address related to the read request and the secondconfirmation means determines that the address related to the readrequest is an address completing an alternate-address process.

A recording method provided by the present invention is a recordingmethod designed for the recording medium described above. The recordingmethod includes: a confirmation step of determining whether or not datahas been recorded at an address related to a data-writing request towrite data in the main data area on the basis of the written/unwrittenstate indication information; a determination step of determiningwhether or not an alternate-address process using the alternate area andthe second alternate-address management information area can be carriedout; a first write step of writing data at the address related to thedata-writing request and updating the written/unwritten state indicationinformation if a determination result obtained at the confirmation stepindicates that data has not been recorded at the address related to thedata-writing request; and a second write step of writing data related tothe data-writing request in the alternate area as well as updating thealternate-address management information and the written/unwritten stateindication information if a determination result obtained at theconfirmation step indicates that data has been recorded at the addressrelated to the data-writing request whereas a determination resultobtained at the determination step indicates that the alternate-addressprocess can be carried out.

A reproduction method provided by the present invention is areproduction method designed for the recording medium described above.The reproduction method includes: a first confirmation step ofdetermining whether or not data has been recorded at an address relatedto a read request to read out data from the main data area on the basisof the written/unwritten state indication information; a secondconfirmation step of determining whether or not the address related tothe read request to read out data from the main data area is an addresscompleting an alternate-address process on the basis of thealternate-address management information; a first read step of readingout data from the address related to the read request if a determinationresult obtained at the first confirmation step indicates that data hasbeen recorded at the address related to the read request and adetermination result obtained at the second confirmation step indicatesthat the address related to the read request is not an addresscompleting an alternate-address process; and a second read step ofreading out data related to the read request from the alternate area onthe basis of the alternate-address management information if adetermination result obtained at the first confirmation step indicatesthat data has been recorded at the address related to the read requestand a determination result obtained at the second confirmation stepindicates that the address related to the read request is an addresscompleting an alternate-address process.

That is to say, the write-once recording medium provided by the presentinvention includes a regular recording/reproduction area, an alternatearea, a first alternate-address management information and a secondalternate-address management information area. In addition,written/unwritten state indication information is recorded. Byadditionally recording alternate-address management information relatedto an alternate-address process in the second alternate-addressmanagement information area, the second alternate-address managementinformation area can be used as an area for implementing renewal ofdata.

In addition, the written/unwritten state indication information is usedas information for determining whether or not data has been recorded ineach data unit (or a cluster) on the recording medium. Thus, it ispossible to implement management of defects and renewal of data inwrite-once media.

When the recording apparatus receives a data-writing request, forexample, the written/unwritten state indication information can be usedas information for determining whether or not data has been recorded atan address specified in the request. If data has been recorded at theaddress specified in the request, data to be written is recorded in thealternate area. In addition, by updating alternate-address managementinformation through addition of information on the alternate-addressprocess carried out in recording the data to be written in the alternatearea, virtually, a data renewal is implemented. Defect management canalso be executed by updating alternate-address management informationthrough addition of information on the alternate-address process carriedout in recording the data to be written in the alternate area due to adefect existing at the address specified in the request.

When the reproduction apparatus receives a data reproduction request,the written/unwritten state indication information can be used asinformation for determining whether or not data has been recorded at anaddress specified in the request. If data has been recorded at theaddress specified in the request, the data to be reproduced is read outfrom the recording medium. If the address specified in the datareproduction request is an address shown in most recently updatedalternate-address management information, the data to be reproduced isread out from an alternate destination address shown in the mostrecently updated alternate-address management information, that is, thedata to be reproduced is read out from an address in the alternate area.Thus, it is possible to correctly read out data resulting from a renewalor data subjected to an alternate-address process in the past due to theexistence of a defect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory diagram showing the area structure of a diskprovided by an embodiment of the present invention;

FIG. 2 is an explanatory diagram showing the structure of a one-layerdisk provided by the embodiment;

FIG. 3 is an explanatory diagram showing the structure of a two-layerdisk provided by the embodiment;

FIG. 4 is an explanatory diagram showing a DMA of a disk provided by theembodiment;

FIG. 5 is a diagram showing the contents of a DDS of a disk provided bythe embodiment;

FIG. 6 is a diagram showing the contents of a DFL of a disk provided bythe embodiment;

FIG. 7 is a diagram showing defect list management information of a DFLand TDFL of a disk provided by the embodiment;

FIG. 8 is a diagram showing alternate-address information of a DFL andTDFL of a disk provided by the embodiment;

FIG. 9 is an explanatory diagram showing a TDMA of a disk provided bythe embodiment;

FIG. 10 is an explanatory diagram showing a space bitmap of a diskprovided by the embodiment;

FIG. 11 is an explanatory diagram showing a TDFL of a disk provided bythe embodiment;

FIG. 12 is an explanatory diagram showing a TDDS of a disk provided bythe embodiment;

FIG. 13 is an explanatory diagram showing an ISA and OSA of a diskprovided by the embodiment;

FIG. 14 is an explanatory diagram showing a data-recording order in aTDMA of a disk provided by the embodiment;

FIG. 15 is an explanatory diagram showing a utilization stage of a TDMAof the two-layer disk provided by the embodiment;

FIG. 16 is a block diagram of a disk drive provided by the embodiment;

FIG. 17 shows a flowchart representing a data-writing process providedby the embodiment;

FIG. 18 shows a flowchart representing a user-data-writing processprovided by the embodiment;

FIG. 19 shows a flowchart representing an overwrite function processprovided by the embodiment;

FIG. 20 shows a flowchart representing a process of generatingalternate-address information in accordance with by the embodiment;

FIG. 21 shows a flowchart representing a data-fetching process providedby the embodiment;

FIG. 22 shows a flowchart representing a TDFL/space-bitmap updateprocess provided by the embodiment;

FIG. 23 shows a flowchart representing a process of restructuringalternate-address information in accordance with the embodiment;

FIG. 24 is an explanatory diagram showing the process of restructuringalternate-address information in accordance with the embodiment;

FIG. 25 shows a flowchart representing a process of converting a diskprovided by the embodiment into a compatible disk in accordance with theembodiment;

FIG. 26 is an explanatory diagram showing a TDMA of a disk provided byanother embodiment;

FIG. 27 is an explanatory diagram showing a TDDS of a disk provided bythe other embodiment;

FIG. 28 is an explanatory diagram showing an ISA and OSA of a diskprovided by the other embodiment;

FIGS. 29A and 29B are each an explanatory diagram showing spare areafull flags provided by the other embodiment;

FIG. 30 shows a flowchart representing a data-writing process providedby the other embodiment;

FIG. 31 shows a flowchart representing a process of setting a renewalfunction in accordance with the other embodiment;

FIG. 32 shows a flowchart representing a data-fetching process providedby the other embodiment; and

FIG. 33 shows a flowchart representing a TDFL/space-bitmap updateprocess provided by the other embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description explains an embodiment provided by the presentinvention as an embodiment implementing an optical disk and a disk driveemployed in a recording apparatus and/or a reproduction apparatus as adisk drive designed for the optical disk. The description compriseschapters arranged in the following order:

-   1: Disk Structure-   2: DMAs-   3: First TDMA Method    -   3-1: TDMAs    -   3-2: ISAs and OSAs    -   3-3: TDMA-Using Method-   4: Disk Drive-   5: Operations for the First TDMA Method    -   5-1: Data Writing    -   5-2: Data Fetching    -   5-3: Updating of the TDFL/Space Bitmap    -   5-4: Conversion into Compatible Disks-   6: Effects of the First TDMA Method-   7: Second TDMA Method    -   7-1: TDMAs    -   7-2: ISAs and OSAs-   8: Operations for the Second TDMA Method    -   8-1: Data Writing    -   8-2: Data Fetching    -   8-3: Updating of the TDFL/Space Bitmap and Conversion into        Compatible Disks-   9: Effects for the Second TDMA Method    1: Disk Structure

First of all, an optical disk provided by the embodiment is explained.The optical disk can be implemented by a write-once optical diskreferred to as the so-called blue-ray disk. The blue-ray disk pertainsto the category of high-density optical disks.

Typical physical parameters of the high-density optical disk provided bythe embodiment are explained as follows.

The disk size of the optical disk provided by the embodiment isexpressed in terms of a diameter of 120 mm and a disk thickness of 1.2mm. That is to say, from the external-appearance point of view, theoptical disk provided by the embodiment is similar to a disk of a CD(Compact Disk) system and a disk of a DVD (Digital Versatile Disk)system.

As a recording/reproduction laser, the so-called blue laser is used. Byusing an optical system having a high NA of typically 0.85, setting thetrack pitch at a small value of typically 0.32 microns and setting theline density at a high value of typically 0.12 microns per bit, it ispossible to implement a user-data storage capacity of about 23 Gbyte to25 Gbyte for an optical disk with a diameter of 12 cm.

In addition, a two-layer disk is also developed. A two-layer disk is anoptical disk having two recording layers. In the case of a two-layerdisk, a user-data capacity of about 50 G can be achieved.

FIG. 1 is an explanatory diagram showing the layout (or the areastructure) of the entire disk.

The recording area of the disk includes a lead-in zone on the innermostcircumference, a data zone on a middle circumference and a lead-out zoneon the outermost circumference.

The lead-in zone, the data zone and the lead-out zone serve as recordingand reproduction areas as follows. A prerecorded information area PIC onthe innermost side of the lead-in zone is a reproduction-only area. Anarea starting with a management/control information area of the lead-inzone and ending with the lead-out zone is used as a write-once areaallowing data to be written therein only once.

In the reproduction-only area and the write-once area, a spiralrecording track is created as a wobbling groove. The wobbling grooveserves as a tracking guide in a tracing operation using a laser spot.The wobbling groove is thus a recording track, which data is recordedonto or read out from.

It is to be noted that, this embodiment assumes an optical disk allowingdata to be recorded on the groove. However, the scope of the presentinvention is not limited to the optical disk with such a recordingtrack. For example, the present invention can also be applied to anoptical disk adopting a land recording-technique whereby data isrecorded on a land between two adjacent grooves. In addition, thepresent invention can also be applied to an optical disk adopting aland/groove recording-technique whereby data is recorded on a land and agroove.

In addition, the groove used as a recording track in an optical disk hasa shape wobbled by a wobbling signal. Thus, a disk drive for such anoptical disk detects both edge positions of the groove from a reflectedlight beam of a laser spot radiated to the groove. Then, by extractingcomponents fluctuating in the radial direction of the disk asfluctuations of both the edge positions in an operation to move thelaser spot along the recording track, the wobble signal can bereproduced.

This wobble signal is modulated by information on addresses of recordinglocations on the recording track. The information on addresses includesphysical addresses and other additional information. Thus, bydemodulating the wobble signal to produce the information on addresses,the disk drive is capable of controlling addresses, at which data are tobe recorded or reproduced.

The lead-in zone shown in FIG. 1 is an area on the inner side acircumference having a typical radius of 24 mm.

An area between a circumference with a radius of 22.2 mm and acircumference with a radius of 23.1 mm in the lead-in zone is theprerecorded information area PIC.

The prerecorded information area PIC is used for storingreproduction-only information as the wobbling state of the groove. Thereproduction-only information includes disk information such asrecording/reproduction power conditions, information on areas on thedisk and information used for copy protection. It is to be noted thatthese pieces of information can also be recorded on the disk as embosspits or the like.

A BCA (Burst Cutting Area) not shown in the figure may be provided on acircumference on the inner side of the prerecorded information area PICin some cases. The BCA is used for storing a unique ID peculiar to thedisk recording medium in such a state that the ID cannot be renewed. Theunique ID is recorded marks created in a concentric-circle shape to formrecorded data in a bar-code format.

An area between a circumference with a radius of 23.1 mm and acircumference with a radius of 24.0 mm in the lead-in zone is amanagement/control information area.

The management/control information area has a predetermined area formatto include a control data area, a DMA (Defect Management Area), a TDMA(Temporary Defect Management Area), a test write area (OPC) and a bufferarea.

The control data area included in the management/control informationarea is used for recording management/control information such as a disktype, a disk size, a disk version, a layer structure, a channel-bitlength, BCA information, a transfer rate, data-zone positioninformation, a recording line speed and recording/reproduction laserpower information.

The test write area (OPC) included in the management/control informationarea is used for a trial writing process carried out in setting datarecording/reproduction conditions such as a laser power to be used inrecording/reproduction operations. That is, the test write area is aregion for adjusting the recording/reproduction conditions.

In the case of an ordinary optical disk, the DMA included in themanagement/control information area is used for recordingalternate-address management information for managing defects. In thecase of a write-once optical disk provided by the embodiment, however,the DMA is used for recording not only the alternate-address managementinformation of defects but also management/control information forimplementing data renewals in the optical disk. In this case,particularly, the DMA is used for recording ISA management informationand OSA management information, which will be described later.

In order to make renewal of data possible by making use of analternate-address process, the contents of the DMA must also be updatedwhen data is renewed. For updating the contents of the DMA, the TDMA isprovided.

Alternate-address management information is added and/or recorded in theTDMA and updated from time to time. Last (most recent) alternate-addressmanagement information recorded in the TDMA is eventually transferred tothe DMA.

The DMA and the TDMA will be described later in detail.

The area on the circumferences with radii in the range 24.0 to 58.0 mmexternal to the lead-in zone is used as a data zone. The data zone is anarea, which user data is actually recorded into and reproduced from. Thestart address ADdts and end address ADdte of the data zone are includedin the data zone position information recorded in the control data areadescribed earlier.

An ISA (Inner Spare Area) is provided on the innermost circumference ofthe data zone. On the other hand, an OSA (Outer Spare Area) is providedon the outermost circumference of the data zone. As will be describedlater, the ISA and the OSA are each used as an alternate area providedfor defects and for implementing data renewals (overwriting).

The ISA begins from the start position of the data zone and includes apredetermined number of clusters each having a size of 65,536 bytes.

On the other hand, the OSA includes a predetermined number of clusters,which terminate at the end position of the data zone. The sizes of theISA and the OSA are described in the DMA.

A user-data area in the data zone is an area sandwiched by the ISA andthe OSA. This user-data area is an ordinary recording/reproduction area,which user data is generally recorded into and reproduced from.

The start address ADus and end address ADue of the user-data area definethe location of the user-data area and are recorded in the DMA.

The area on the circumferences with radii in the range 58.0 to 58.5 mmexternal to the data zone is the lead-out zone. The lead-out zone is amanagement/control information area having a predetermined format toinclude a control data area, a DMA and a buffer area. Much like thecontrol data area included in the lead-in zone, the control data area ofthe lead-out zone is used for storing various kinds ofmanagement/control information. By the same token, much like the DMAincluded in the lead-in zone, the DMA of the lead-out zone is used as anarea for recording management information of the ISA and managementinformation of the OSA.

FIG. 2 is a diagram showing a typical structure of themanagement/control information area on a one-layer disk having only onerecording layer.

As shown in the figure, in addition to undefined segments (reservedsegments), the lead-in zone includes a variety of areas such as DMA 2,an OPC (a test write area), a TDMA and DMA 1. On the other hand, inaddition to undefined segments (reserved segments), the lead-out zoneincludes a variety of areas such as DMA 3 and DMA 4.

It is to be noted that the control data area described above is notshown in the figure. This is because, in actuality, a portion of thecontrol data area is used as a DMA for example. Since the structure of aDMA is an essential of the present invention, the control data area isnot shown in the figure.

As described above, the lead-in and lead-out zones include four DMAs,i.e., DMA 1 to DMA 4. DMA 1 to DMA 4 are each used as an area forrecording the same alternate-address management information.

However, a TDMA is provided as an area used for temporarily recordingalternate-address management information and, every time analternate-address process is carried out due to renewal of data or adefect, new alternate-address management information is additionallyrecorded in the TDMA to update the information already recorded therein.

Thus, till the disk is finalized, for example, the DMAs are not used.Instead, the alternate-address management is carried out and newalternate-address management information is added to the TDMA and/orrecorded in the TDMA. As the disk is finalized, alternate-addressmanagement information recorded on the TDMA most recently is transferredto the DMAs so that the alternate-address process based on the DMA canbe carried out.

FIG. 3 is a diagram showing a two-layer disk having two recordinglayers. The first recording layer is referred to as layer 0 and thesecond recording layer is called layer 1. Data is recorded onto andreproduced from layer 0 in a direction from the inner side of the diskto the outer side thereof, as same as in the case of one-layer disk. Onthe other hand, data is recorded onto and reproduced from layer 1 in adirection from the outer side of the disk to the inner side thereof.

The value of the physical address increases in the directions. That isto say, the value of the physical address on layer 0 increases in thedirection from the inner side of the disk to the outer side thereof, andthe value of the physical address on layer 1 increases in the directionfrom the outer side of the disk to the inner side thereof.

Much like the one-layer disk, the lead-in zone on layer 0 includes avariety of areas such as DMA 2, an OPC (a test write area), TDMA 0 andDMA 1. Since the outermost circumference on layer 0 is not a lead-outzone, it is referred to simply as outer zone 0, which includes DMA 3 andDMA 4.

The outermost circumference on layer 1 is referred to simply as outerzone 1, which includes DMA 3 and DMA 4. The innermost circumference oflayer 1 is a lead-out zone, which includes a variety of areas such asDMA 2, an OPC (a test write area), TDMA 1 and DMA 1.

As described above, the lead-in zone, outer zones 0 and 1 and thelead-out zone include eight DMAs. In addition, each of the recordinglayers includes a TDMA.

The size of the lead-in zone on layer 0 and the size of the lead-outzone on layer 1 are equal to the size of the lead-in zone on theone-layer disk. On the other hand, the sizes of outer zones 0 and 1 areequal to the size of the lead-out zone on the one-layer disk.

2: DMAs

The data structure of each DMA recorded in the lead-in zone and thelead-out zone is explained below. In the case of a two-layer disk, theDMAs also include the DMAs in outer zones 0 and 1.

FIG. 4 is a diagram showing the structure of the DMA.

The size of the DMA shown in the figure is 32 clusters (=32×65,536bytes). It is to be noted that a cluster is the smallest data-recordingunit. Of course, the size of a DMA is not limited to 32 clusters. InFIG. 4, the 32 clusters are identified by cluster numbers 1 to 32, whicheach indicate a data position of each content of the DMA. The size ofeach content is expressed as a cluster count.

In the DMA, cluster numbers 1 to 4 identify four clusters forming asegment for recording a DDS (disc definition structure), which describesthe disc in detail.

The contents of the DDS will be described later by referring to FIG. 5.In actually, since the size of the DDS is one cluster, four identicalDDSes are recorded in the segment.

Cluster numbers 5 to 8 identify four clusters forming a segment forrecording DFL #1, which is the first recording area of a DFL (defectlist). The data structure of the defect list will be described later byreferring to FIG. 6. The size of data stored in the defect list is fourclusters forming a list of information on alternate addresses.

Cluster numbers 9 to 12 identify four clusters forming a segment forrecording DFL #2, which is the second recording area of the defect list.The second recording area is followed by the third and subsequentrecording areas DFL #3 to DFL #6, which each have a size of fourclusters. The four-cluster segment DFL #7 used as the seventh recordingarea of the defect list is identified by cluster numbers 29 to 32.

As is obvious from the above description, the DMA having a size of 32clusters includes seven recording areas of the defect list, i.e., DFL #1to DFL #7.

In a write-once optical disk allowing data to be recorded therein onceas is the case with the disk provided by the embodiment, in order torecord contents of a DMA, it is necessary to carry out a processreferred to as ‘finalize’. In this case, the same contents are recordedin seven recording areas DFL #1 to DFL #7.

FIG. 5 is a diagram showing the data structure of the contents of theDDS recorded at the beginning of the DMA shown in FIG. 4. As describedabove, the DDS has a size of one cluster (=65,536 bytes).

In the figure, byte 0 is the position of the beginning of the DDS havinga size of 65,536 bytes. A byte-count column shows the number of bytesincluded in each data content.

Two bytes indicated by byte positions 0 to 1 are used as bytes forrecording “DS”, which is a DDS identifier indicating that this clusteris the DDS.

One byte indicated by byte position 2 is used as a byte for recording aDDS format number of the version of the DDS format.

Four bytes indicated by byte positions 4 to 7 are used as bytes forrecording the number of times the DDS has been updated. It is to benoted that, in this embodiment, in the finalize process,alternate-address management information is additionally written intothe DMA itself instead of being used for updating the DMA. Thealternate-address management information is stored in the TDMA beforebeing written into the DMA in the finalize process. Thus, when thefinalize process is eventually carried out, a TDDS (temporary DDS) ofthe TDMA contains the number of times the TDDS has been updated. Theaforementioned number of times the DDS has been updated is the number oftimes the TDDS has been updated.

Four bytes indicated by byte positions 16 to 19 are used as bytes forrecording AD_DRV, which is the start physical sector address of a drivearea in the DMA.

Four bytes indicated by byte positions 24 to 27 are used as bytes forrecording AD_DFL, which is the start physical sector address of a defectlist DFL in the DMA.

Four bytes indicated by byte positions 32 to 35 are used as bytes forrecording a PSN (physical sector number or a physical sector address) ofthe start position of the user-data area in the data zone. That is tosay, the four bytes are used as bytes for recording a PSN indicating theposition of an LSN (logical sector number) of 0.

Four bytes indicated by byte positions 36 to 39 are used as bytes forrecording an LSN (logical sector number) of the end position of theuser-data area in the data zone.

Four bytes indicated by byte positions 40 to 43 are used as bytes forrecording the size of the ISA in the data zone. The ISA is the ISA of aone-layer disk or the ISA on layer 0 of a two-layer disk.

Four bytes indicated by byte positions 44 to 47 are used as bytes forrecording the size of each OSA in the data zone.

Four bytes indicated by byte positions 48 to 51 are used as bytes forrecording the size of the ISA in the data zone. The ISA is the ISA onlayer 1 of a two-layer disk.

One byte indicated by byte position 52 is used as a byte for recordingspare area full flags showing whether or not data can be renewed byusing an ISA or an OSA. That is to say, the spare area full flag areused to indicate that the ISA and the OSA are being used entirely.

Byte positions other than the byte positions described above arereserved (or undefined) and all filled with codes of 00h.

As described above, the DDS is used as an area for storing the addressesof the user-data area, the sizes of each ISA and each OSA and spare areafull flags. That is to say, the DDS is used for storing information formanaging and controlling areas of each ISA and each OSA in the datazone.

Next, the data structure of the defect list DFL is explained byreferring to FIG. 6. As explained earlier by referring to FIG. 4, thedefect list DFL is recorded in an area having a size of four clusters.

In the defect list DFL shown in FIG. 6, a byte-position column showsdata positions of each data content of the defect list having a size offour clusters. It is to be noted that one cluster is 32 sectorsoccupying 65,536 bytes. Thus, one sector has a size of 2,048 bytes.

A byte-count column shows the number of bytes composing each datacontent.

The first 64 bytes of the defect list DFL are used as bytes forrecording management information of the defect list DFL. The managementinformation of the defect list DFL includes information indicating thatthis cluster is the defect list DFL, a version, the number of times thedefect list DFL has been updated and the number of entries forming thedefect list DFL.

The bytes following the 64^(th) byte are used as bytes for recordingcontents of each entry of the defect list DFL. Each entry isalternate-address information ati having a length of eight bytes.

A terminator having a length of eight bytes serves as analternate-address end immediately following ati #N, which is the lastone of pieces of effective alternate-address information.

In this DFL, an area following the alternate-address end is filled upwith 00h codes till the end of the clusters.

The defect-list management information having a length of 64 bytes isshown in FIG. 7.

Two bytes starting with a byte at byte position 0 are used as bytes forrecording a character string DF representing the identifier of thedefect list DFL.

One byte at byte position 2 is used as a byte for recording the formatnumber of the defect list DFL.

Four bytes starting with a byte at byte position 4 are used as bytes forrecording the number of times the defect list DFL has been updated. Itis to be noted that this value is actually the number of times the TDFL(temporary defect list) to be described later has been updated and,thus, a value transferred from the TDFL.

Four bytes starting with a byte at byte position 12 are used as bytesfor recording the number of entries in the defect list DFL, that is, thenumber of pieces of alternate-address information ati.

Four bytes starting with a byte at byte position 24 are used as bytesfor recording cluster counts indicating the sizes of free areasavailable in the alternate areas ISA 0, ISA 1, OSA 0 and OSA 1.

Byte positions other than the byte positions described above arereserved and all filled with codes of 00h.

FIG. 8 is a diagram showing the data structure of an alternate-addressinformation ati. The data structure includes information showing thecontents of an entry completing an alternate-address process.

In the case of a one-layer disk, the total number of pieces ofalternate-address information ati can be up to a maximum of 32,759.

Each piece of alternate-address information ati comprises eight bytes(or 64 bits, i.e., bits b63 to b0). Bits b63 to b60 are used as bits forrecording status 1, which is the status of the entry. In the defect listDFL, the status is set at a value of ‘0000’ indicating an ordinaryalternate-address process entry. Other values of the status will beexplained later in a description of the alternate address in the TDFL ofthe TDMA.

Bits b59 to b32 are used as bits for recording the PSN (physical sectoraddress) of the first sector in an alternate source cluster. That is tosay, in this data structure, a cluster subjected to an alternate-addressprocess due to a defect or renewal of data is expressed by the physicalsector address PSN of the first sector of the cluster.

Bits b31 to b28 are reserved. It is to be noted that these bits can alsobe used as bits for recording status 2, which is other status in thisentry.

Bits b27 to b0 are used as bits for recording the physical sectoraddress PSN of the first sector in an alternate destination cluster.That is to say, in this data structure, a destination cluster requiredin an alternate-address process due to a defect or renewal of data isexpressed by the physical sector address PSN of the first sector of thecluster.

As described above, the alternate-address information ati is treated asan entry showing an alternate source cluster and an alternatedestination cluster. Then, such an entry is cataloged in the defect listDFL having a structure shown in FIG. 6.

In the DMA, information on an alternate-address management informationis recorded in a data structure like the one described above. Asexplained above, however, these kinds of information are recorded in aprocess to finalize the disk. In this process, most recent informationon an alternate-address management information is transferred from theTDMA to the DMA.

Information on defect processing and information on an alternate-addressmanagement carried out due to renewal of data are recorded in the TDMAdescribed below and updated from time to time.

3: First TDMA Method

3-1: TDMAs

The following description explains the TDMA (temporary DMA) provided inthe management/control information area as shown in FIGS. 2 and 3. Muchlike the DMA, the TDMA is used as an area for recording information onalternate-address processes. Every time an alternate-address process iscarried out to follow renewal of data or follow detection of a defect,information on the alternate-address process is added to the TDMA orrecorded in the TDMA as an update.

FIG. 9 is a diagram showing the data structure of the TDMA.

The size of the TDMA is typically 2,048 clusters. As shown in thefigure, the first cluster indicated by a cluster number of 1 is used asa cluster for recording a space bitmap for layer 0. A space bitmapcomprises bits each representing a cluster of a main data area includingthe data zone as well as a management/control area including the lead-inzone and the lead-out zone (and the outer zones in the case of atwo-layer disk). The value of each bit is write existence/non-existenceinformation indicating whether or not data has been written into acluster represented by the bit. All clusters ranging from the lead-inzone to the lead-out zone (including the outer zones in the case of atwo-layer disk) are each represented by a bit of the space bitmap asdescribed above, and the size of the space bitmap itself is one cluster.

A cluster indicated by a cluster number of 2 is used as a cluster forrecording a space bitmap for layer 1 (or the second layer). It is to benoted that, in the case of a one-layer disk, a space bitmap for layer 1is of course unnecessary.

If an alternate-address process is carried out in, for example, anoperation to change data contents, a TDFL (temporary defect list) isadditionally recorded to a cluster at the beginning of an unrecordedarea in the TDMA. Thus, in the case of a two-layer disk, the first TDFLis recorded in an area starting from the position indicated by a clusternumber of 3 as shown in the figure. In the case of a one-layer disk, aspace bitmap for layer 1 is not necessary as described above. Thus, thefirst TDFL is recorded in an area starting from the position indicatedby a cluster number of 2. Then, every time an alternate-address processis carried out thereafter, a TDFL is additionally recorded at asubsequent cluster position without providing a gap between thesubsequent cluster position and the preceding cluster position.

The size of a TDFL is in the range 1 to up to 4 clusters. Since a spacebitmap shows recording states of clusters, the bitmap is updated everytime data is written into any of the clusters to update the cluster.When the space bitmap is updated, much like a TDFL, a new space bitmapis additionally recorded in a TDMA area starting from the beginning of afree area in the TDMA.

That is to say, a space bitmap and/or a TDFL is additionally recorded inthe TDMA from time to time.

It is to be noted that the configurations of a space bitmap and a TDFLwill be described later. Anyway, a TDDS (temporary disc definitionstructure) is recorded in the last 2,048-byte sector of a cluster usedfor recording a space bitmap and the last 2,048-byte sector of 1 to 4clusters used for recording a TDFL. The TDDS is detailed information onthe optical disk.

FIG. 10 is a diagram showing the data structure of a space bitmap.

As described above, each bit of a space bitmap represents the recordingstate of one cluster on the disk, that is, each bit indicates whether ornot data has been recorded in the cluster represented thereby. Forexample, if data has not been recorded in a cluster, a bit representingthe cluster is set at 1. It is to be noted that, in the case of atwo-layer disk, a space bitmap is provided for each layer andinformation recorded in one of the space bitmaps is independent ofinformation recorded in the other space bitmap.

For one sector=2,048 bytes, clusters on a layer having a storagecapacity of 25 GB can be represented by a space bitmap with a size of 25sectors. Since one cluster comprises 32 sectors, the space bitmap itselfcan be formed from one cluster.

In the data structure of a space bitmap shown in FIG. 10, a clusterallocated as the bitmap comprises 32 sectors, i.e., sectors 0 to 31. Abyte-position column shows byte positions of each of the sectors.

Sector 0 at the beginning of the space bitmap is used as a sector forrecording management information of the bitmap.

Two bytes at byte positions 0 and 1 in sector 0 are used as bytes forrecording an UB, which is an unallocated space bitmap ID (identifier).

One byte at byte position 2 is used as a byte for recording a formatversion such as a version of 00h.

Four bytes starting from byte position 4 are used as bytes for recordinga layer number indicating whether this space bitmap corresponds to layer0 or layer 1.

48 bytes starting from byte position 16 are used as bytes for recordingbitmap information.

The bitmap information comprises pieces of zone information for threezones, i.e., the inner zone, the data zone and the outer zone. Thepieces of zone information are zone information for the inner zone, zoneinformation for the data zone and zone information for the outer zone.

The size of each of the pieces of zone information is 16 bytes. Each ofthe pieces of zone information comprises a start cluster first PSN, astart byte position of bitmap data, a validate bit length in bitmap dataand a reserved area, which each have a size of four bytes.

The start cluster first PSN is a PSN (physical sector address)indicating a start position of the zone on the disk. That is to say, thePSN is a start address, which is used when the zone is mapped onto thespace bitmap.

The start byte position of bitmap data is a byte count indicating thestart position of bitmap data for the zone as a position relative to theunallocated space bit map identifier located at the beginning of thespace bit map.

The validate bit length in bitmap data is also a byte count representingthe amount of bitmap data of the zone.

Actual bitmap data is recorded on sector 1 in an area starting from byteposition 0 of the sector. Sector 1 is the second sector of the spacebitmap. In this area, one sector of the space bitmap represents 1 GBdata. The actual bitmap data is followed by reserved areas ending withan area immediately preceding sector 31, which is the last sector of thespace bitmap. The reserved areas are filled with codes of 00h.

Sector 31, which is the last sector of the space bitmap, is used as asector for recording a TDDS.

The pieces of bitmap information described above are managed as follows.First of all, the description explains a space bitmap with the layernumber at byte position 4 indicating layer 0. That is to say, thedescription explains a space bitmap for a one-layer disk or a spacebitmap for layer 0 of a two-layer disk.

In this case, the zone information for the inner zone is information forthe inner zone of layer 0, that is, information for a lead-in zone.

The start cluster first PSN of the zone is a PSN of the start positionof the lead-in zone as shown by a solid-line arrow.

The start byte position of bitmap data is used for recording informationindicating the position of bitmap data corresponding to the lead-in zonein the space bitmap as shown by a dashed-line arrow, that is,information indicating byte position 0 of sector 1.

The value of the validate bit length in bitmap data is the size of thebitmap data for the lead-in zone.

The zone information for the data zone is information on the data zoneof layer 0.

The start cluster first PSN of the zone is a PSN of the start positionof the data zone as shown by a solid-line arrow.

The start byte position of bit map data is used for recordinginformation indicating the position of bitmap data corresponding to thedata zone in the space bitmap as shown by a dashed-line arrow, that is,information indicating byte position 0 of sector 2.

The value of the validate bit length in bitmap data is the size of thebitmap data for the data zone.

The zone information for the outer zone is information for the outerzone of layer 0, that is, information for a lead-out zone on a one-layerdisk or outer zone 0 of a two-layer disk.

The start cluster first PSN of the zone is a PSN of the start positionof the lead-out zone or outer zone 0 as shown by a solid-line arrow.

The start byte position of bitmap data is used for recording informationindicating the position of bitmap data corresponding to the lead-outzone (or outer zone 0) in the space bitmap as shown by a dashed-linearrow, that is, information indicating byte position 0 of sector N.

The value of the validate bit length in bitmap data is the size of thebitmap data for the lead-out zone or outer zone 0.

Next, the description explains a space bitmap with the layer number atbyte position 4 indicating layer 1. That is to say, the descriptionexplains a space bitmap for layer 1 of a two-layer disk.

In this case, the zone information for the inner zone is information forthe inner zone of layer 1, that is, information for a lead-out zone.

The start cluster first PSN of the zone is a PSN of the start positionof the lead-out zone as shown by a dotted-line arrow. Since the addressdirection on layer 1 is a direction from an outer side to an inner side,a position indicated by the dotted-line arrow is a start position.

The start byte position of bit map data is used for recordinginformation indicating the position of bitmap data corresponding to thelead-out zone in the space bitmap as shown by a dashed-line arrow, thatis, information indicating byte position 0 of sector 1.

The value of the validate bit length in bitmap data is the size of thebitmap data for the lead-out zone.

The zone information for the data zone is information on the data zoneof layer 1.

The start cluster first PSN of the zone is a PSN of the start positionof the data zone as shown by a dotted-line arrow.

The start byte position of bitmap data is used for recording informationindicating the position of bitmap data corresponding to the data zone inthe space bitmap as shown by a dashed-line arrow, that is, informationindicating byte position 0 of sector 2.

The value of the validate bit length in bitmap data is the size of thebitmap data for the data zone.

The zone information for the outer zone is information for the outerzone 1 of layer 1.

The start cluster first PSN of the zone is a PSN of the start positionof the outer zone 1 as shown by a dotted-line arrow.

The start byte position of bitmap data is used for recording informationindicating the position of bitmap data corresponding to outer zone 1 inthe space bitmap as shown by a dashed-line arrow. The information isinformation indicating byte position 0 of sector N.

The value of the validate bit length in bitmap data is the size of thebitmap data for outer zone 1.

Next, the data structure of a TDFL is explained. As described above, aTDFL is recorded in a free area following a space bitmap in a TDMA.Every time an updating operation is carried out, a TDFL is recorded atthe beginning of the remaining free area.

FIG. 11 is a diagram showing the data structure of a TDFL.

The TDFL comprises 1 to 4 clusters. By comparing with the DFL shown inFIG. 6, it is obvious that the contents of the TDFL are similar to thoseof the DFL in that the first 64 bytes of the defect list are used asbytes for recording management information of the defect list, the bytesfollowing the 64^(th) byte are used as bytes for recording contents ofpieces of alternate-address information ati each having a length of 8bytes, and a terminator having a length of 8 bytes serves as analternate-address end immediately following ati #N, which is the lastone of pieces of effective alternate-address information.

However, the TDFL composed of 1 to 4 clusters is different from the DFLin that a DDS (or a TDDS) is recorded in 2,048 bytes composing the lastsector of the TDFL.

It is to be noted that, in the case of the TDFL, an area preceding thelast sector of a cluster to which the alternate-address informationterminator pertains is filled up with codes of 00h. As described above,the last sector is used as a sector for recording a TDDS. If thealternate-address information terminator pertains to the last sector ofa specific cluster, an area between the specific cluster and the lastsector of a cluster immediately preceding the specific cluster is filledup with codes of 0 and the last sector of the immediately precedingcluster is used as a sector for recording a TDDS.

The defect-list management information having a size of 64 bytes isidentical with the defect-list management information explained earlierby referring to FIG. 7 as information included in of the defect listDFL.

However, as the number of times the defect list has been updated, thefour bytes starting with a byte at byte position 4 are used as bytes forrecording the sequence number of the defect list. That is to say, asequence number included in defect-list management information in a mostrecent TDFL is the number of times the defect list has been updated.

Besides, the four bytes starting with a byte at byte position 12 areused as bytes for recording the number of entries, that is, the numberof pieces of alternate-address information ati. In addition, the fourbytes starting with a byte at byte position 24 are used as bytes forrecording values of cluster counts at the time the TDFL is updated. Thiscluster counts represent the sizes of free areas available in thealternate areas ISA 0, ISA 1, OSA 0 and OSA 1.

The data structure of the alternate-address information ati in the TDFLis similar to the data structure shown in FIG. 8 as the structure of thealternate-address information ati in the DFL. The alternate-addressinformation ati is included in the TDFL as an entry showing an alternatesource cluster and an alternate destination cluster, which are involvedin an alternate-address process. Such an entry is cataloged in thetemporary defect list TDFL having a data structure shown in FIG. 11.

In the case of the TDFL, however, the value of status 1 included in thealternate-address information ati in the TDFL may have a value of 0101or 1010 in addition to 0000.

Status 1 having a value of 0101 or 1010 indicates that analternate-address process carried out on a plurality of physicallycontinuous clusters is a burst transfer process, which handles theclusters collectively.

To be more specific, status 1 having a value of 0101 indicates that thestart sector physical address of an alternate source cluster and thestart sector physical address of an alternate destination cluster, whichare included in the alternate-address information ati, are respectivelythe physical address of the first sector in the first cluster of thephysically continuous clusters serving as the alternate source and thephysical address of the first sector in the first cluster of thephysically continuous clusters serving as the alternate destination.

On the other hand, status 1 having a value of 1010 indicates that thestart sector physical address of an alternate source cluster and thestart sector physical address of an alternate destination cluster, whichare included in the alternate-address information ati are respectivelythe physical address of the first sector in the last cluster of thephysically continuous clusters serving as the alternate source and thephysical address of the first sector in the last cluster of thephysically continuous clusters serving as the alternate destination.

Thus, in an alternate-address process collectively treating a pluralityof physically continuous clusters, it is not necessary to catalog anentry describing the alternate-address information ati for each of allthe clusters. Instead, it is necessary to specify only one entry ofalternate-address information ati including two physical addresses offirst sectors in first clusters and another entry of alternate-addressinformation ati including two physical addresses of first sectors inlast clusters as described above.

As described above, basically, the TDFL has a data structure identicalwith that of a DFL. However, the TDFL is characterized in that the sizeof the TDFL can be extended to up to four clusters, the last sector isused as a sector for recording a TDDS, and management of burst transferscan be executed by using alternate-address information ati.

As shown in FIG. 9, the TDMA is used as an area for recording spacebitmaps and TDFLs. As described earlier, however, the 2,048-byte lastsector of each of the space bitmaps and each of the TDFLs is used as asector for recoding a TDDS (temporary disc definition structure).

FIG. 12 is a diagram showing the structure of the TDDS.

The TDDS occupies one sector having a size of 2,048 bytes. The TDDS hasthe same contents as the DDS in a DMA. It is to be noted that, eventhough the DDS has a size of one cluster consisting of 65,536 bytes,only a portion not beyond byte position 52 is virtually defined ascontents of the DDS as explained earlier by referring to FIG. 5. That isto say, actual contents are recorded in the first sector of the cluster.Thus, in spite of the fact that the TDDS has a size of only one sector,the TDDS covers all the contents of the DDS.

As is obvious from comparison of FIG. 12 with FIG. 5, contents of theTDDS at byte positions 0 to 53 are identical with those of the DDS. Itis to be noted, however, that bytes starting from byte position 4 areused as bytes for recording the sequence number of the TDDS, bytesstarting from byte position 16 are used as bytes for recording thephysical address of the first sector in a drive area in the TDMA andbytes starting from byte position 24 are used as bytes for recording thephysical address AD_DFL of the first sector of the TDFL in the TDMA.

Bytes at byte position 1,024 and subsequent byte positions in the TDDSare used as bytes for recording information, which does not exist in theDDS.

Four bytes starting from byte position 1,024 are used as bytes forrecording the physical address LRA of a sector on an outermostcircumference included in the user-data area as a circumference on whichuser data has been recorded.

Four bytes starting from byte position 1,028 are used as bytes forrecording the physical address AD_BP0 of the first sector in a mostrecent space bitmap for layer 0 in the TDMA.

Four bytes starting from byte position 1,032 are used as bytes forrecording the physical address AD_BP1 of the first sector in a mostrecent space bitmap for layer 1 in the TDMA.

One byte at byte position 1,036 is used as a byte for recording a flagfor controlling the use of an overwrite function.

Bytes at byte positions other than the byte positions described aboveare reserved and filled with codes of 00h.

As described above, the TDDS includes addresses in the user-data area,ISA and OSA sizes and spare area full flags. That is to say, the TDDSincludes management/control information for managing ISAs and OSAs inthe data zone. At this point, the TDDS is similar to the DDS.

Also as described above, the TDDS also includes pieces of informationsuch as the physical address AD_BP0 of the first sector in the effectivemost recent space bitmap for layer 0, the physical address AD_BP1 of thefirst sector in the effective most recent space bitmap for layer 1 andthe physical address AD_DFL of the first sector in the effective mostrecent TDFL (temporary DFL).

Since a TDDS is recorded in the last sector of the space bitmap and thelast sector of the TDFL every time a space bitmap or a TDFL is added,the recorded TDDS is a new TDDS. Thus, in the TDMA shown in FIG. 9, aTDDS included in a space bitmap added last or a TDDS included in a TDFLadded last is the most recent TDDS. In the most recent TDDS, the mostrecent space bitmap and the most recent TDFL are shown.

3-2: ISAs and OSAs

FIG. 13 is a diagram showing positions of each ISA and each OSA.

An ISA (inner space area) and an OSA (outer space area) are each an areaallocated in the data zone as an alternate area used in analternate-address process carried out on a defective cluster.

In addition, an ISA or an OSA is also used in an operation to write newdata into a desired address as an alternate area for actually recordingthe new data supposed to be written into the desired address, at whichother data has been recorded previously. The operation to write the newdata into the desired address is thus an operation to renew the otherdata with the new data.

FIG. 13A is a diagram showing the positions of an ISA and an OSA on aone-layer disk. As shown in the diagram, the ISA is located on theinnermost-circumference side of the data zone whereas the OSA is locatedon the outermost-circumference side of the data zone.

On the other hand, FIG. 13B is a diagram showing the positions of eachISA and each OSA on a two-layer disk. As shown in the diagram, ISA 0 islocated on the innermost-circumference side of the data zone on layer 0whereas the OSA 0 is located on the outermost-circumference side of thedata zone on layer 0. On the other hand, ISA 1 is located on theinnermost-circumference side of the data zone on layer 1 whereas the OSA1 is located on the outermost-circumference side of the data zone onlayer 1.

On the two-layer disk, the size of ISA 0 may be different from that ofISA 1. However, the size of OSA 0 is equal to that of OSA 1.

The sizes of the ISA (or ISA 0 and ISA 1) and the sizes of the OSA (orOSA 0 and OSA 1) are defined in the DDS and the TDDS, which have beendescribed earlier.

The size of the ISA is determined at an initialization time and remainsfixed thereafter. However, the size of the OSA may be changed even afterdata has been recorded therein. That is to say, the OSA size recorded inthe TDDS can be changed in an operation to update the TDDS to increasethe size of the OSA.

An alternate-address process using the ISA or the OSA is carried out asfollows. An operation to renew data is taken as an example. For example,new data is written into the user-data zone. To be more specific, thedata is written into a cluster, in which existing data has already beenwritten previously. That is to say, a request is made as a request torenew the existing data. In this case, since the disk is recognized as awrite-once optical disk, the new data cannot be written into thecluster. Thus, the new data is written into a cluster in the ISA or theOSA. This operation is referred to as an alternate-address process.

This alternate-address process is managed as the alternate-addressinformation ati described above. The alternate-address information atiis treated as a TDFL entry including the address of a cluster, in whichthe existing data has been recorded from the very start, as an alternatesource address. The TDFL entry of the alternate-address information atialso includes the address of an ISA or OSA cluster, in which the newdata has been written as alternate-address data, as an alternatedestination address.

That is to say, in the case of renewal of existing data,alternate-address data is recorded in the ISA or the OSA and thealternate-address process carried out on the data locations for therenewal of the existing data is controlled as alternate-addressinformation ati cataloged on the TDFL in the TDMA. Thus, while the diskis a write-once optical disk, virtually, renewal of data is implemented.In other words, as seen from the OS of a host system, a file system orother systems, renewal of data is implemented.

The alternate-address process can also be applied to management ofdefects in the same way. To put it in detail, if a cluster is determinedto be a defective area, by carrying out the alternate-address process,data supposed to be written in the cluster is written in a cluster ofthe ISA or the OSA. Then, for the management of this alternate-addressprocess, one alternate-address information ati is cataloged as an entryon the TDFL.

3-3: TDMA-Using Method

As described above, every time data is renewed or an alternate-addressprocess is carried out, a space bitmap and a TDFL in a TDMA are updated.

FIG. 14 is a diagram showing the state of updating contents of a TDMA.

FIG. 14A shows a state in which a space bitmap for layer 0, a spacebitmap for layer 1 and a TDFL have been recorded in the TDMA.

As described above, the last sector of each of the space bitmaps and thelast sector of the TDFL are each used for recording a TDDS (temporaryDDS). They are referred to as TDDS 1, TDDS 2 and TDDS 3.

In the case of the state shown in FIG. 14A, the TDFL is related to mostrecently written data. Thus, TDDS 3 recorded in the last sector of theTDFL is the most recent TDDS.

As explained earlier by referring to FIG. 12, this TDDS includes AD BP0,AD BP1 and AD DFL. AD BP0 and AD BP1 are information showing thelocations of effective most recent space bitmaps. On the other hand, ADDFL is information showing the location of an effective most recentTDFL. In the case of TDDS 3, AD BP0, AD BP1 and AD DFL are pieces ofeffective information pointing to the locations of the space bitmaps andthe TDFL as shown by a solid-line arrow, a dashed-line arrow and adotted-line arrow respectively. That is to say, AD DFL in TDDS 3 is usedas an address for specifying a TDFL including TDDS 3 itself as aneffective TDFL. On the other hand, AD BP0 and AD BP1 in TDDS 3 are usedas addresses for specifying space bitmaps for layers 0 and 1respectively as effective space bitmaps.

Later on, data is written and, since the space bitmap for layer 0 isupdated, a new space bitmap for layer 0 is added to the TDMA. As shownin FIG. 14B, the new space bitmap is recorded at the beginning of a freearea. In this case, TDDS 4 recorded in the last sector of the new spacebitmap becomes the most recent TDDS. AD BP0, AD BP1 and AD DFL in TDDS 4are used as addresses for specifying pieces of effective information.

To be more specific, AD BP0 in TDDS 4 is used as an address forspecifying a space bitmap for layer 0 as a space bitmap, which includesTDDS 4 itself and serves as effective information. Much like the stateshown in FIG. 14A, AD BP1 in TDDS 4 is used as an address for specifyinga space bitmap for layer 1 as effective information, and AD DFL in TDDS4 is used as an address for specifying a TDFL as an effective TDFL.

Later on, data is written again and, since the space bitmap for layer 0is updated, a new space bitmap for layer 0 is added to the TDMA. Asshown in FIG. 14C, the new space bitmap is recorded at the beginning ofthe free area. In this case, TDDS 5 recorded in the last sector of thenew space bitmap becomes the most recent TDDS. AD BP0, AD BP1 and AD DFLin TDDS 5 are used as addresses for specifying pieces of effectiveinformation.

To be more specific, AD BP0 in TDDS 4 is used as an address forspecifying a space bitmap for layer 0 as a space bitmap, which includesTDDS 4 itself and serves as effective information. Much like the stateshown in FIGS. 14A and 14B, AD BP1 is used as an address for specifyinga space bitmap for layer 1 as effective information, and AD DFL is usedas an address for specifying a TDFL as an effective TDFL.

As described above, when a TDFL and/or a space bitmap are updated, aTDDS recorded in the last sector of the most recent information includesaddresses indicating effective information such as space bitmaps and aTDFL, which are included in the TDMA. The effective information isdefined as the most recent space bitmaps and the most recent TDFL, whichare cataloged in the TDMA before a finalize process.

Thus, the disk drive is capable of grasping an effective TDFL andeffective space bitmaps by referring to a TDDS included in a lastrecorded TDFL or a last recorded space bitmap recorded in the TDMA.

By the way, FIG. 14 is a diagram showing the state of updating contentsof a TDMA for a two-layer disk. That is to say, the TDMA includes aspace bitmap for layer 0 and a space bitmap for layer 1.

The two space bitmaps and the TDFL are initially cataloged in the TDMAfor layer 0. That is to say, only the TDMA for layer 0 is used and,every time a TDFL and/or a space bitmap are updated, the new TDFL and/orthe new space bitmap are added to the TDMA as shown in FIG. 14.

The TDMA for layer 1 as the second layer is used after the TDMA forlayer 0 has been all used up.

Then, the TDMA for layer 1 is also used for cataloging TDFLs and/orspace bitmaps one after another by starting from the beginning of theTDMA.

FIG. 15 is a diagram showing a state in which the TDMA for layer 0 isall used up after recording a TDFL or a space bitmap N times. Then, aTDFL or a space bitmap is cataloged continuously in the TDMA providedfor layer 1 to serve as a continuation of the TDMA provided for layer 0as shown in FIG. 14C.

In the state shown in FIG. 15, after the TDMA for layer 0 has been usedup, two space bitmaps for layer 1 are further cataloged in the TDMA forlayer 1. In this state, TDDS N+2 recorded in the last sector of the mostrecent space bitmap for layer 1 is the most recent TDDS. Much like thestate shown in FIG. 14, in the most recent TDDS, AD BP0, AD BP1 and ADDFL point to pieces of effective information as shown by a solid-linearrow, a dashed-line arrow and a dotted-line arrow respectively. That isto say, AD BP1 in TDDS N+2 is used as an address for specifying a spacebitmap for layer 1 as a space bitmap, which includes TDDS N+2 itself andserves as effective information. On the other hand, AD BP0 in TDDS N+2is used as an address for specifying a space bitmap for layer 0, thatis, the same space bitmap as that shown in FIG. 14C, and AD DFL in TDDSN+2 is used as an address for specifying a TDFL as effective informationor most recently updated information.

It is needless to say that, if the TDFL, the space bitmap for layer 0 orthe space bitmap for layer 1 is updated thereafter, the updated TDFL orspace bitmap is cataloged at the beginning of a free area in the TDMAfor layer 1.

As described above, the TDMAs for recording layers 0 and 1 are used oneafter another for cataloging updated TDFLs and space bitmaps. Thus, theTDMAs for the recording layers can be used jointly as a large singleTDMA. As a result, a plurality of DMAs can be utilized with a highdegree of efficiency.

In addition, by searching only a TDDS recorded last without regard towhether the TDMA is provided for layer 0 or 1, an effective TDFL and/orspace bitmap can be grasped.

In this embodiment, a one-layer disk and a two-layer disk are assumed asdescribed above. It is to be noted, however, that a disk having three ormore recording layers is also conceivable. Also in the case of a diskhaving three or more recording layers, the TDMAs for the layers can beused one after another in the same way.

4: Disk Drive

The following description explains a recording/reproduction apparatusserving as a disk drive for the write-once optical disks describedabove.

The disk drive provided by the embodiment is capable of forming a layoutof a write-once optical disk in a state explained earlier by referringto FIG. 1 by formatting the disk in a state wherein, typically, only theprerecorded information area PIC shown in FIG. 1 has been created but nowrite-once area has been formed. In addition, the disk drive recordsdata into the user-data area of the disk formatted in this way andreproduces data from the user-data. If necessary, the disk drives alsoupdates a TDMA by recording information therein and records data into anISA or an OSA.

FIG. 16 is a diagram showing the configuration of the disk drive.

A disk 1 is the write-once optical disk described above. The disk 1 ismounted on a turntable not shown in the figure. In arecording/reproduction operation, the turntable is driven into rotationat a CLV (constant linear velocity) by a spindle motor 52.

An optical pickup (optical head) 51 reads out ADIP addresses embedded onthe disk 1 as a wobbling shape of a groove track and management/controlinformation as information prerecorded on the disk 1.

At an initialization/formatting time or in an operation to record userdata onto the disk 1, the optical pickup 51 records management/controlinformation and user data onto a track in a write-once area. In areproduction operation, on the other hand, the optical pickup 51 readsout data recorded on the disk 1.

The optical pickup 51 includes a laser diode, a photo detector, anobjective lens and an optical system, which are not shown in the figure.The laser diode is a device serving as a source for generating a laserbeam. The photo detector is a component for detecting a beam reflectedby the disk 1. The objective lens is a component serving as an outputterminal of the laser beam. The optical system is a component forradiating the laser beam to a recording face of the disk 1 by way of theobjective lens and leading the reflected beam to the photo detector.

In the optical pickup 51, the objective lens is held by a biaxialmechanism in such a way that the mechanism is capable of moving theobjective lens in tracking and focus directions.

In addition, the entire optical pickup 51 can be moved in the radialdirection of the disk 1 by a thread mechanism 53.

The laser diode included in the optical pickup 51 is driven to emit alaser beam by a drive current generated by a laser driver 63 as a drivesignal.

The photo detector employed in the optical pickup 51 detects informationconveyed by a beam reflected by the disk 1, converts the detectedinformation into an electrical signal proportional to the lightintensity of the reflected beam and supplies the electrical signal to amatrix circuit 54.

The matrix circuit 54 has a current/voltage conversion circuit, which isused for converting a current output by the photo detector comprising aplurality of light-sensitive devices into a voltage, and a matrixprocessing/amplification circuit for carrying out matrix processing togenerate necessary signals. The necessary signals include ahigh-frequency signal (or a reproduced-data signal) representingreproduced data as well as a focus error signal and a tracking errorsignal, which are used for servo control.

In addition, a push-pull signal is also generated as a signal related towobbling of the groove. The signal related to wobbling of the groove isa signal for detecting the wobbling of the groove.

It is to be noted that the matrix circuit 54 may be physicallyintegrated inside the optical pickup 51.

The reproduced-data signal output by the matrix circuit 54 is suppliedto a reader/writer circuit 55. The focus error signal and the trackingerror signal, which are also generated by the matrix circuit 54, aresupplied to a servo circuit 61. The push-pull signal generated by thematrix circuit 54 is supplied to a wobble circuit 58.

The reader/writer circuit 55 is a circuit for carrying out processingsuch as a binary conversion process on the reproduced-data signal and aprocess to generate a reproduction clock signal by adopting a PLLtechnique to generate data read out by the optical pickup 51. Thegenerated data is then supplied to a modulation/demodulation circuit 56.

The modulation/demodulation circuit 56 comprises a functional memberserving as a decoder in a reproduction process and a functional memberserving as an encoder in a recording process.

In a reproduction process, the modulation/demodulation circuit 56implements demodulation process for run-length limited code as decodingprocess on the basis of the reproduction clock signal.

An ECC encoder/decoder 57 is a component for carrying out an ECCencoding process to add error correction codes to data to be recordedonto the disk 1 and an ECC decoding process for correcting errorsincluded in data reproduced from the disk 1.

At a reproduction time, data demodulated by the modulation/demodulationcircuit 56 is stored in an internal memory to be subjected to errordetection/correction processing and processing such as a de-interleaveprocess to generate the eventual reproduced data.

The reproduced data obtained as a result of a decoding process carriedout by the ECC encoder/decoder 57 is read out from the internal memoryand transferred to an apparatus connected to the disk drive inaccordance with a command given by a system controller 60. An example ofthe apparatus connected to the disk drive is an AV (Audio-Visual) system120.

As described above, the push-pull signal output by the matrix circuit 54as a signal related to the wobbling state of the groove is processed inthe wobble circuit 58. The push-pull signal conveying ADIP informationis demodulated in the wobble circuit 58 into a data stream composingADIP addresses. The wobble circuit 58 then supplies the data stream toan address decoder 59.

The address decoder 59 decodes the data received thereby to generateaddresses and then supplies the addresses to the system controller 60.

The address decoder 59 also generates a clock signal by carrying out aPLL process using the wobble signal supplied by the wobble circuit 58and supplies the clock signal to other components for example as arecording-time encode clock signal.

The push-pull signal output by the matrix circuit 54 as a signal relatedto the wobbling state of the groove is a signal originated from theprerecorded information PIC. In the wobble circuit 58, the push-pullsignal is subjected to a band-pass filter process before being suppliedto the reader/writer circuit 55, which carries out a binary conversionprocess to generate a data bit stream. The data bit stream is thensupplied to the ECC encoder/decoder 57 for carrying out ECC-decode andde-interleave processes to extract data representing the prerecordedinformation. The extracted prerecorded information is then supplied tothe system controller 60.

On the basis of the fetched prerecorded information, the systemcontroller 60 is capable of carrying out processes such as processing toset a variety of operations and copy protect processing.

At a recording time, data to be recorded is received from the AV system120. The data to be recorded is buffered in a memory employed in the ECCencoder/decoder 57.

In this case, the ECC encoder/decoder 57 carries out processes on thebuffered data to be recorded. The processes include processing to adderror correction codes, interleave processing and processing to addsub-codes.

The data completing the ECC encoding process is subjected to ademodulation process such as demodulation adopting an RLL (1-7) PPmethod in the modulation/demodulation circuit 56 before being suppliedto the reader/writer circuit 55.

In these encoding processes carried out at a recording time, the clocksignal generated from the wobble signal as described above is used asthe encoding clock signal, which serves as a reference signal.

After completing these encoding processes, the data to be recorded issupplied to the reader/writer circuit 55 to be subjected to recordingcompensation processing such as fine adjustment of a recording power toproduce a power value optimum for factors including characteristics ofthe recording layer, the spot shape of the laser beam and the recordinglinear speed as well as adjustment of the shape of the laser drivepulse. After completing the recording compensation processing, the datato be recorded is supplied to the laser driver 63 as laser drive pulses.

The laser driver 63 passes on the laser drive pulses to the laser diodeemployed in the optical pickup 51 to drive the generation of a laserbeam from the diode. In this way, pits suitable for the recorded dataare created on the disk 1.

It is to be noted that the laser driver 63 includes the so-called APC(Auto Power Control) circuit for controlling the laser output to a fixedvalue independent of ambient conditions such as the ambient temperatureby monitoring the laser output power. A detector is provided in theoptical pickup 51 to serve as a monitor for monitoring the laser outputpower. The system controller 60 gives a target value of the laser outputpower for each of recording and reproduction processes. The level of thelaser output is controlled to the target value for the recording orreproduction process.

The servo circuit 61 generates a variety of servo drive signals from thefocus error signal and the tracking error signal, which are receivedfrom the matrix circuit 54, to carry out servo operations. The servodrive signals include focus, tracking and thread servo drive signals.

To put it concretely, the focus and tracking drive signals are generatedin accordance with the focus error signal and the tracking error signalrespectively to drive respectively focus and tracking coils of thebiaxial mechanism employed in the optical pickup 51. Thus, tracking andfocus servo loops are created as loops comprising the optical pickup 51,the matrix circuit 54, the servo circuit 61 and the biaxial mechanism.

In addition, in accordance with a track jump command received from thesystem controller 60, the servo circuit 61 turns off the tracking servoloop and carries out a track jump operation by outputting a jump drivesignal.

On top of that, the servo circuit 61 generates a thread drive signal onthe basis of a thread error signal and an access execution controlsignal, which is received from the system controller 60, to drive thethread mechanism 53. The thread error signal is obtained as alow-frequency component of the tracking error signal. The threadmechanism 53 has a mechanism comprising a transmission gear, a threadmotor and a main shaft for holding the optical pickup 51. The threadmechanism 53 drives the thread motor in accordance with the thread drivesignal to slide the optical pickup 51 by a required distance. It is tobe noted that the mechanism itself is not shown in the figure.

A spindle servo circuit 62 controls the spindle motor 52 to rotate at aCLV.

The spindle servo circuit 62 obtains a clock signal generated in a PLLprocess for the wobble signal as information on the present rotationalspeed of the spindle motor 52 and compares the present rotational speedwith a predetermined CLV reference speed to generate a spindle errorsignal.

In addition, a reproduction clock signal generated at a datareproduction time by a PLL circuit employed in the reader/writer circuit55 is used as the reference clock signal of a decoding process as wellas the information on the present rotational speed of the spindle motor52. Thus, by comparing this reproduction clock signal with thepredetermined CLV reference speed, a spindle error signal can begenerated.

Then, the spindle servo circuit 62 outputs the spindle drive signal,which is generated in accordance with the spindle error signal, to carryout the CLV rotation of the spindle motor 52.

In addition, the spindle servo circuit 62 also generates a spindle drivesignal in accordance with a spindle kick/brake control signal receivedfrom the system controller 60 to carry out operations to start, stop,accelerate and decelerate the spindle motor 52.

A variety of operations carried out by the servo system and therecording/reproduction system as described above are controlled by thesystem controller 60 based on a microcomputer.

The system controller 60 carries out various kinds of processing inaccordance with commands received from the AV system 120.

When a write instruction (or a command to write data) is received fromthe AV system 120, for example, the system controller 60 first of allmoves the optical pickup 51 to an address into which the data is to bewritten. Then, the ECC encoder/decoder 57 and themodulation/demodulation circuit 56 carry out the encoding processesdescribed above on the data received from the AV system 120. Examples ofthe data are video and audio data generated in accordance with a varietyof methods such as MPEG2. Subsequently, as described above, thereader/writer circuit 55 supplies laser drive pulses representing thedata to the laser driver 63 in order to actually record the data on thedisk 1.

On the other hand, when a read command to read out data such as MPEG2video data from the disk 1 is received from the AV system 120, forexample, the system controller 60 first of all carries out a seekoperation to move the optical pickup 51 to a target address at which thedata is to be read out from the disk 1. That is to say, the systemcontroller 60 outputs a seek command to the servo circuit 61 to drivethe optical pickup 51 to make an access to a target address specified inthe seek command.

Thereafter, necessary control of operations is executed to transfer dataof a specified segment to the AV system 120. That is to say, the data isread out from the disk 1, processing such as the decoding and bufferingprocesses is carried out in the reader/writer circuit 55, themodulation/demodulation circuit 56 and the ECC encoder/decoder 57, andthe requested data is transferred to the AV system 120.

It is to be noted that, in the operations to record data into the disk 1and reproduce data from the disk 1, the system controller 60 is capableof controlling accesses to the disk 1 and the recording/reproductionoperations by using ADIP addresses detected by the wobble circuit 58 andthe address decoder 59.

In addition, at predetermined points of time such as the time the disk 1is mounted on the disk drive, the system controller 60 reads out aunique ID from the BCA on the disk 1 in case the BCA exists on the disk1 and prerecorded information (PIC) recorded on the disk 1 as a wobblinggroove from the reproduction-only area.

In this case, control of seek operations is executed with the BCA andthe prerecorded data zone PR set as targets of the seek operations. Thatis to say, commands are issued to the servo circuit 61 to make accessesby using the optical pickup 51 to the innermost-circumference side ofthe disk 1.

Later on, the optical pickup 51 is driven to carry out reproductiontracing to obtain a push-pull signal as information conveyed by areflected beam. Then, decoding processes are carried out in the wobblecircuit 58, reader/writer circuit 55 and ECC encoder/decoder 57 togenerate BCA information and prerecorded information as reproduced data.

On the basis of the BCA information and the prerecorded information,which are read out from the disk 1 as described above, the systemcontroller 60 carries out processing such as a process to set laserpowers and a copy protect process.

In the configuration shown in FIG. 16, a cache memory 60 a is employedin the system controller 60. The cache memory 60 a is used for holdingtypically a TDFL and/or a space bitmap, which are read out from the TDMArecorded on the disk 1, so that the TDFL and/or the space bitmap can beupdated without making an access to the disk 1.

When the disk 1 is mounted on the disk drive, for example, the systemcontroller 60 controls components of the disk drive to read out a TDFLand/or a space bitmap from the TDMA recorded on the disk 1 and storethem in the cache memory 60 a.

Later on, when an alternate-address process is carried out to renew dataor due to a defect, the TDFL or the space bitmap stored in the cachememory 60 a is updated.

Every time an alternate-address process is carried out to write or renewdata in the disk 1 and the TDFL or the space bitmap is updated, forexample, the updated TDFL or space bitmap can be additionally catalogedin the TDMA recorded on the disk 1. By doing so, however, the TDMArecorded on the disk 1 will be used up at an early time.

In order to solve this problem, only the TDFL or the space bitmap storedin the cache memory 60 a is updated till the disk 1 is ejected from thedisk drive. As the disk 1 is ejected from the disk drive, for example,the last (most recent) TDFL or space bitmap stored in the cache memory60 a is transferred to the TDMA recorded on the disk 1. In this way, theTDMA recorded on the disk 1 is updated only after the TDFL and/or thespace bitmap, which are stored in the cache memory 60 a, has beenupdated a large number of times so that the amount of the TDMAconsumption can be reduced.

The explanation given thereafter is based on a method to reduce theamount of consumption of the TDMA recorded on the disk 1 by using thecache memory 60 a in processing such as a recording process to bedescribed later. It is needless to say, nevertheless, that the presentinvention can be implemented without the cache memory 60 a. Without thecache memory 60 a, however, every time a TDFL or a space bitmap isupdated, the updated TDFL or the updated space bitmap must be catalogedin the TDMA recorded on the disk 1.

By the way, the typical configuration of the disk drive shown in FIG. 16is the configuration of a disk drive connected to the AV system 120.However, the disk drive provided by the present invention can beconnected to an apparatus such as a personal computer.

In addition, the disk drive may be designed into a configuration thatcannot be connected to an apparatus. In this case, unlike theconfiguration shown in FIG. 16, the disk drive includes an operationunit and a display unit or an interface member for inputting andoutputting data. That is to say, data is recorded onto a disk andreproduced from the disk in accordance with an operation carried out bythe user, and a terminal is required as a terminal for inputting andoutputting the data.

Of course, other typical configurations are conceivable. For example,the disk drive can be designed as a recording-only apparatus or areproduction-only apparatus.

5: Operations for the First TDMA Method

5-1: Data Writing

By referring to flowcharts shown in FIGS. 17 to 20, the followingdescription explains processing carried out by the system controller 60in a process to record data onto the disk 1 mounted on the disk drive.

It is to be noted that, at the time the data-writing process explainedbelow is carried out, the disk 1 has already been mounted on the diskdrive, and a TDFL as well as a space bitmap have been transferred from aTDMA on the disk 1 mounted on the disk drive to the cache memory 60 a.

In addition, when a request for a write operation or a read operation isreceived from a host apparatus such as the AV system 120, the targetaddress is specified in the request as a logical sector address. Thedisk drive carries out logical/physical address conversion processing toconvert the logical sector address into a physical sector address butthe description of the conversion process for each request from time totime is omitted.

It is to be noted that, in order to convert a logical sector addressspecified by a host into a physical sector address, it is necessary toadd ‘the physical address of the first sector in a user-data area’recorded in the TDDS to the logical sector address.

Assume that a request to write data into address N has been receivedfrom a host apparatus such as the AV system 120 by the system controller60. In this case, the system controller 60 starts processing representedby the flowchart shown in FIG. 17. First of all, at a step F101, a spacebitmap stored in the cache memory 60 a is referred to in order todetermine whether or not data has been recorded in a cluster at thespecified address. The space bitmap stored in the cache memory 60 a is aspace bitmap updated most recently.

If no data has been recorded at the specified address, the flow of theprocessing goes on to a step F102 to carry out a process to write userdata into the address as represented by the flowchart shown in FIG. 18.

If data has already been recorded at the specified address so that theprocess to write the data of this time can not be implemented, on theother hand, the flow of the processing goes on to a step F103 to carryout an overwrite process represented by the flowchart shown in FIG. 19.

The process to write user data into the address as represented by theflowchart shown in FIG. 18 is a process requested by a command to writethe data into the address at which no data has been recorded. Thus, theprocess to write user data into the address as represented by theflowchart shown in FIG. 18 is an ordinary write process. If an error isgenerated in the course of the write process due to a defect such as aninjury on the disk 1, however, an alternate-address process may becarried out in some cases.

First of all, at a step F111, the system controller 60 executes controlto write the data into the specified address. That is to say, theoptical pickup 51 is driven to make an access to the specified addressand record the data of the write request into the address.

If the operation to write the data into the address is completednormally, the flow of the processing goes on from the step F112 to thestep F113 at which the space bitmap stored in the cache memory 60 a isupdated. To put it in detail, the space bitmap is searched for a bitcorresponding to a cluster in which the data has been written this time,and the bit is set to a value indicating that data has been written intothe cluster. Then, the execution of the processing for the write requestis ended.

If the operation carried out at the step F111 to write the data into theaddress is not completed normally and an alternate-address processfunction is in an on state, on the other hand, the flow of theprocessing goes on from the step F112 to the step F114.

It is to be noted that the step F112 is executed also to determinewhether or not the alternate-address process function is in an on stateby checking whether or not an ISA and/or an OSA have been defined. If atleast either an ISA or an OSA has been defined, an alternate-addressprocess can be carried out. In this case, the alternate-address processfunction is determined to be in an on state.

An ISA or an OSA is determined to have been defined if the size of theISA or the OSA in the TDDS of the TDMA has been set at a value otherthan a zero. That is to say, at a formatting time of the disk 1, atleast either an ISA or an OSA is defined as an actually existingalternate area by specifying its size at a value other than a zero in aTDDS and recording the TDDS in the first TDMA. As an alternative, forexample, an OSA can be redefined by setting its size at a value otherthan a zero in an operation to update a TDDS in a TDMA.

After all, if at least either an ISA or an OSA exists, thealternate-address process function is determined to be in an on state.In this case, the flow of the processing goes on to the step S114.

If the determination result obtained at the step F112 indicates thatneither an ISA nor an OSA exists, indicating that the alternate-addressprocess function has been made ineffective, on the other hand, the flowof the processing goes on to the step S113. It is to be noted that, atthis step, the space bitmap stored in the cache memory 60 a is searchedfor a bit corresponding to a cluster at the specified address and thebit is set at a value indicating that data has been recorded in thecluster. Then, the execution of the processing is ended. In this case,however, the write request is ended in an error.

In spite of the fact that a write error has been generated, at the bitin the space bitmap, a flag indicating that data has been recorded inthe cluster corresponding to the bit is set in the same way as a normaltermination of the processing. The setting of the flag means that thedefective area is managed by using the space bitmap as a cluster inwhich data has been recorded. Thus, even if a request is received as arequest to write data into the defective area, in which the error hasbeen generated, by referring to the space bitmap, the processing of therequest can be carried out with a high degree of efficiency.

As described above, if the alternate-address process function isdetermined at the step F112 to be in an on state, the flow of theprocessing goes on to the step F114, first of all, to determine whetheror not the alternate-address process can be actually carried out.

In order to carry out the alternate-address process, the spare area,that is, either the ISA or the OSA, must have a free area for at leastrecording the data requested in the write operation. In addition, theTDMA must have a margin allowing an entry of the alternate-addressinformation ati for managing this alternate-address process to be added,that is, allowing the TDFL to be updated.

It is possible to determine whether or not the ISA or the OSA has such afree area by checking the number of unused ISA/OSA clusters included inthe defect-list management information shown in FIG. 7. As describedearlier, the defect-list management information is included in a TDFL asshown in FIG. 11.

If at least either the ISA or the OSA has a free area and the TDMA has amargin for update, the flow of the processing carried out by the systemcontroller 60 goes on from the step F114 to a step F115 at which theoptical pickup 51 is driven to make an access to the ISA or the OSA andrecord the data requested in the write operation into the free area inthe ISA or the OSA respectively.

Then, at the next step F116, after the write operation requiring thealternate-address process, the TDFL and the space bitmap, which havebeen stored in the cache memory 60 a, are updated.

To put it in detail, the contents of the TDFL are updated by newlyadding an entry of the alternate-address information ati representingthe present alternate-address process as shown in FIG. 8 to the TDFL. Inaddition, in accordance with the addition of such an entry, the numberof cataloged DFL entries in the defect-list management information shownin FIG. 7 is increased while the number of unused ISA/OSA clusters inthe defect-list management information shown in FIG. 7 is decreased. Ifthe alternate-address process is carried out on one cluster, the numberof cataloged DFL entries is incremented by one while the number ofunused ISA/OSA clusters is decremented by one. It is to be noted that aprocess to generate the alternate-address information ati will bedescribed later.

In addition, a bit included in the space bitmap as a bit correspondingto a cluster at the address, at which an error of the requested writeoperation has been generated, is set at a value indicating that data hasbeen recorded in the cluster. By the same token, a bit included in thespace bitmap as a bit corresponding to an ISA or OSA cluster, in whichthe data has been actually recorded, is set at a value indicating thatdata has been recorded in the cluster.

Then, the execution of the processing of the write request is ended. Inthis case, however, a write error has been generated at the addressspecified in the write request, by carrying out the alternate-addressprocess, the write operation can be completed. From the standpoint ofthe host apparatus, the processing of the write is ended normally.

If the determination result obtained at the step F114 indicates thatneither the ISA nor the OSA has a free area or the TDMA does not have amargin for TDFL to be updated, the flow of the processing carried out bythe system controller 60 goes on to a step F117 at which an error reportis returned to the host apparatus and the execution of the processing isended.

If the determination result obtained at the step F101 of the flowchartshown in FIG. 17 indicates that data has already been recorded at theaddress specified in the write request made by the host apparatus asevidenced by the fact that a bit included in the space bitmap as a bitcorresponding to a cluster at the address has been set at a valueindicating that data has been recorded in the cluster, the flow of theprocessing goes on to the step F103 as described earlier. At this step,the overwrite function process represented by the flowchart shown inFIG. 19 is carried out.

The flowchart begins with a step F121 at which the system controller 60determines whether or not the overwrite function or the data renewalfunction is effective. The system controller 60 is capable ofdetermining whether or not the overwrite function is effective byreferring to a flag included in the TDDS shown in FIG. 12 as a flagindicating whether or not the overwrite function is usable.

If the flag indicating whether or not the overwrite function is usableis not set at 1 indicating that the function is not effective, the flowof the processing goes on to a step F122 at which an error reportindicating incorrect specification of the address is returned to thehost apparatus and the execution of the processing is ended.

If the flag indicating whether or not the overwrite function is usableis set at 1 indicating that the data renewal function is effective, onthe other hand, the processing of the data renewal function is started.

In this case, the flow of the processing goes on to a step F123 first ofall to determine whether or not the alternate-address process can becarried out. As described above, in order to carry out thealternate-address process, the spare area, that is, either the ISA orthe OSA, must have a free area for at least recording the data requestedin the write operation and, in addition, the TDMA must have a marginallowing an entry of the alternate-address information ati for managingthis alternate-address process to be added, that is, allowing the TDFLto be updated.

If at least either the ISA or the OSA has a free area and the TDMA has amargin allowing an entry of the alternate-address information ati formanaging this alternate-address process to be added, the flow of theprocessing carried out by the system controller 60 goes on from the stepF123 to a step F124 at which the optical pickup 51 is driven to make anaccess to the ISA or the OSA and record the data requested in the writeoperation into the free area in the ISA or the OSA respectively.

Then, at the next step F125, after the write operation requiringexecution of the alternate-address process, the TDFL and the spacebitmap, which have been stored in the cache memory 60 a, are updated. Toput it in detail, the contents of the TDFL are updated by newly addingan entry of the alternate-address information ati representing thepresent alternate-address process as shown in FIG. 8 to the TDFL.

However, data at the same address may have been renewed before and anentry of the alternate-address information ati representing thealternate-address process for the renewal has thus been cataloged on theTDFL. In such a case, first of all, all pieces of alternate-addressinformation ati cataloged in the TDFL are searched for an entryincluding the address as an alternate source address. Ifalternate-address information ati has been cataloged in the TDFL as anentry including the address as an alternate source address, thealternate destination address included in the alternate-addressinformation ati is changed to the address in the ISA or the OSA. Sincethe TDFL containing such alternate-address information ati as an entryhas been stored in the cache memory 60 a at the present point of time,the change of the alternate destination address of the alternate-addressinformation ati can made with ease. It is to be noted that, without thecache memory 60 a, every time the TDFL recorded on the disk 1 isupdated, the already cataloged entry must be deleted from the TDFLbefore adding a new entry to the TDFL.

If a new entry of the alternate-address information ati is added to theTDFL, the number of cataloged DFL entries in the defect-list managementinformation shown in FIG. 7 is increased while the number of unusedISA/OSA clusters in the defect-list management information shown in FIG.7 is decreased.

In addition, a bit included in the space bitmap as a bit correspondingto an ISA or OSA cluster, in which the data has been actually recorded,is set at a value indicating that data has been recorded in the cluster.

Then, the execution of the processing of the write request is ended. Bycarrying out the processing to use the ISA or the OSA as describedabove, the system controller 60 is capable of coping with a data renewalrequest, which is a request to write data into an address at which datahas been recorded.

If the determination result obtained at the step F123 indicates thatneither the ISA nor the OSA has a free area or the TDMA does not have amargin allowing an entry of the alternate-address information ati formanaging this alternate-address process to be added, on the other hand,the flow of the processing carried out by the system controller 60 goeson to a step F126 at which an error report indicating no free write areais returned to the host apparatus and the execution of the processing isended.

By the way, at the step F116 of the flowchart shown in FIG. 18 and thestep F125 of the flowchart shown in FIG. 19, alternate-addressinformation ati is newly generated for the alternate-address process bythe system controller 60 in processing represented by the flowchartshown in FIG. 20.

The flowchart shown in FIG. 20 begins with a step F151 to determinewhether or not the alternate-address process is a process carried out ona plurality of physically continuous clusters.

If the alternate-address process is a process carried out on a clusteror a plurality of physically discontinuous clusters, the flow of theprocessing goes on to a step F154 at which alternate-address informationati is generated for the cluster or each of the physically discontinuousclusters. In this case, status 1 of the data structure shown in FIG. 8is set at 0000 for each alternate-address information ati as is the casewith the normal alternate-address process. Then, at the next step F155,each alternate-address information ati generated in this way is added tothe TDFL.

If the alternate-address process is a process carried out on a pluralityof physically continuous alternate source and alternate destinationclusters, on the other hand, the flow of the processing goes on to astep F152 at which, first of all, alternate-address information ati isgenerated for clusters at the beginnings of the alternate source andalternate destination clusters, and status 1 of the alternate-addressinformation ati is set at 0101. Then, at the next step F153,alternate-address information ati is generated for clusters at the endsof the alternate source and alternate destination clusters, and status 1of the alternate-address information ati is set at 1010. Then, at thenext step F155, the two pieces of alternate-address information atigenerated in this way are added to the TDFL.

By carrying out the processing described above, even analternate-address process for three or more physically continuousclusters can be managed by using only two pieces of alternate-addressinformation ati.

5-2: Data Fetching

By referring to a flowchart shown in FIG. 21, the following descriptionexplains processing carried out by the system controller 60 to reproducedata from the disk 1 mounted on the disk drive.

Assume that the system controller 60 receives a request to read out datarecorded at an address specified in the request from a host apparatussuch as the AV system 120. In this case, the flowchart representing theprocessing begins with a step F201 at which the system controller 60refers to a space bitmap to determine whether or not data has beenstored in the address specified in the request.

If no data has been stored in the address specified in the request, theflow of the processing goes on to a step F202 at which an error reportindicating that the specified address is an incorrect address isreturned to the host apparatus.

If data has been stored in the address specified in the request, on theother hand, the flow of the processing goes on to a step F203 at whichthe TDFL is searched for alternate-address information ati including thespecified address as an alternate source address in order to determinewhether or not an entry including the specified address has beencataloged on the TDFL.

If alternate-address information ati including the specified address asan alternate source address is not found in the search, the flow of theprocessing goes on from the step F203 to a step F204 at which data isreproduced from an area starting at the specified address before endingthe execution of the processing, which is a normal process to reproducedata from the user-data area.

If the determination result obtained at the step F203 indicates thatalternate-address information ati including the specified address as analternate source address has been found in the search, on the otherhand, the flow of the processing goes on from the step F203 to a stepF205 at which an alternate destination address is acquired from thealternate-address information ati. This alternate destination address isan address in an ISA or an OSA.

Then, at the next step F206, the system controller 60 reads out datafrom the ISA or OSA address, which has been cataloged in thealternate-address information ati as an alternate destination address,and transfers the reproduced data to the host apparatus such as the AVsystem 120 before ending the execution of the processing.

By carrying out the processing described above, even if a request toreproduce data is received after the data has been renewed, the mostrecent data can be reproduced appropriately and transferred to the host.

5-3: Updating of the TDFL/Space Bitmap

In the processing described above, the TDFL stored in the cache memory60 a is updated in case the process to write data into a cluster isaccompanied by an alternate-address process and the space bitmap alsostored in the cache memory 60 a is updated to reflect the data writeprocess. At a certain point of time, the updated TDFL and space bitmapneed to be transferred to the TDMA recorded on the disk 1. That is tosay, it is necessary to update the state of management based onalternate-address processes and the recording state, which are statesrecorded on the disk 1.

It is most desirable to update the TDMA recorded on the disk 1 at apoint of time the disk 1 is about to be ejected from the disk drive eventhough the timing to update the TDMA is not limited to the timing toeject the disk 1. Besides the timing to eject the disk 1, the TDMA canalso be updated when the power supply of the disk drive is turned off orupdated periodically.

FIG. 22 shows a flowchart representing process to update the TDMArecorded on the disk 1. At an ejection time or the like, the systemcontroller 60 determines whether or not it is necessary to update thecontents of the TDMA, that is, whether or not it is necessary to catalogthe updated TDFL or space bitmap in the TDMA. If necessary, a process toupdate information in the TDMA is carried out.

At an ejection time or the like, the system controller 60 carries outprocessing to update the TDFL and/or the space bitmap. This processingstarts at a step F301 of the flowchart shown in FIG. 22.

The flowchart actually begins with a step F302 to determine whether ornot the TDFL stored in the cache memory 60 a has been updated. If theTDFL has been updated, the flow of the processing goes on to a step F303at which a TDDS shown in FIG. 12 is added to the updated TDFL, beingrecorded in the last sector of the TDFL.

Then, at the next step F304, the optical pickup 51 is driven to recordthe TDFL at the beginning of a free area in the TDMA recorded on thedisk 1. It is to be noted that, at that time, since data is newlyrecorded in the TDMA, the space bitmap stored in the cache memory 60 ais also updated.

Then, after the TDFL is recorded in the TDMA, the flow of the processinggoes on to a step F305. The flow of the processing also goes on to thestep F305 from the step F302 because the TDFL was not updated. In eithercase, the space bitmap stored in the cache memory 60 a is checked todetermine whether or not the bitmap has been updated.

If the TDFL has been updated as described above, at least, the spacebitmap has also been updated at that time. This is because analternate-address process has been carried out so that the space bitmaphas also been updated as well in accordance with the alternate-addressprocess. In addition, the space bitmap is also updated in accordancewith an operation to record data in a cluster even if noalternate-address process has been carried out.

If the space bitmap stored in the cache memory 60 a has been updated inone of the situations described above, the flow of the processing goeson to a step F306, at which the TDDS shown in FIG. 12 is added to theupdated space bitmap stored in the cache memory 60 a, being recorded inthe last sector of the space bitmap. Then, at the next step F307, theoptical pickup 51 is driven to record the space bitmap at the beginningof a free area in the TDMA recorded on the disk 1. Finally, theexecution of the processing to record the updated TDFL and/or theupdated space bitmap in the TDMA at an ejection time or the like isended.

It is to be noted that, if no data has been written into the disk 1 atall since the disk 1 was mounted on the disk drive, the flow of theprocessing represented by the flowchart shown in FIG. 22 goes from thestep F302 to the end by way of the step F305 without recording anupdated TDFL and/or an updated space bitmap in the TDMA.

At the steps F304 and F307, the TDFL and the space bitmap are recordedsequentially at the beginning of a free area in the TDMA recorded on thedisk 1 as explained earlier by referring to FIGS. 14 and 15. In the caseof a two-layer disk, the TDMA on layer 0 is used first as an area forrecording the TDFL and the space bitmap and, after no more free area isleft in the TDMA on layer 0, the TDMA on layer 1 is used.

In addition, in the case of both the one-layer disk and the two-layerdisk, a TDDS added to the last TDFL or space bitmap in the TDMA, beingrecorded in the last sector of the last TDFL or the last sector of thelast space bitmap is the effective TDDS, which points to the effectiveTDFL and the effective space bitmap.

By the way, when a TDFL is additionally recorded in the TDMA at the stepF303, F304, a technique may also be adopted as a conceivable techniquefor restructuring pieces of alternate-address information ati stored inthe cache memory 60 a.

FIG. 23 shows a flowchart representing a typical alternate-addressinformation restructure process. This process can be carried outtypically before the step F303 of the flowchart shown in FIG. 22.

At a step F351, pieces of alternate-address information ati cataloged onthe TDFL stored in the cache memory 60 a are searched to verify whetheror not the following condition exists. The source and destinationclusters represented by specific pieces of alternate-address informationati are respectively physical continuation of the source and destinationclusters represented by the other specific pieces of alternate-addressinformation ati.

If such specific pieces of alternate-address information ati were notbeen found in the search, the flow of the processing goes from the stepF352 back to the step F303 of the flowchart shown in FIG. 11 withoutcarrying out any process.

If such two specific pieces of alternate-address information ati werefound in the search, on the other hand, the flow of the processing goeson to a step F353 at which the specific pieces of alternate-addressinformation ati are synthesized for the purpose of restructuring them.

The steps F352 and F353 are executed repeatedly to synthesize any pairof such specific pieces of alternate-address information ati. After allsuch specific pieces of alternate-address information ati are processed,the flow of the processing goes from the step F352 back to the stepF303.

FIG. 24 is an explanatory diagram showing the alternate-addressinformation restructure process.

Assume for example that, as shown in FIG. 24A, requests to write datainto clusters CL1, Cl2, Cl3 and Cl4 are received separately, and data iswritten into clusters CL11, Cl12, Cl13 and Cl14 respectively in an OSAthrough an alternate-address process.

In this case, since the four requests to write data into the clustersare received separately, four pieces of alternate-address informationati are each cataloged as an entry having status 1 of 0000 as shown inFIG. 24B.

However, two pieces of alternate-address information ati having status 1of 0101 and status 1 of 1010 respectively can be applied to fouralternate-address continuous destination clusters CL1, Cl2, Cl3 and Cl4and four alternate-address continuous source clusters CL11, Cl12, Cl13and Cl14 used in this example.

Thus, as shown in FIG. 24C, the four entries can be restructured into astart entry with status 1 of 0101 indicating start source cluster Cl1 aswell as start destination cluster Cl11 and an end entry with status 1 of1010 indicating end source cluster Cl4 as well as end destinationcluster Cl14. As a result, the number of pieces of alternate-addressinformation ati recorded on the disk 1 can be reduced.

It is to be noted that such restructuring of alternate-addressinformation can of course be applied to any pair of entries with status1 of 0101 and 1010 indicating a plurality of continuous source and aplurality of destination clusters as described above. For example, afirst pair of entries represents a plurality of first continuous sourceclusters and a plurality of first continuous destination clusters. Bythe same token, a second pair of entries is a pair provided for aplurality of second continuous source clusters and a plurality of secondcontinuous destination clusters. If the second continuous sourceclusters are a continuation of the first continuous source clusters andthe second continuous destination clusters are a continuation of thefirst continuous destination clusters, the first pair of entries and thesecond pair of entries can be restructured into a new pair of entries.

In addition, if a plurality of continuous source and destinationclusters represented by a pair of entries with status 1 of 0101 andstatus 1 of 1010 as described above are respectively continuations ofsource and destination clusters represented another entry with status 1of 0000, the pair of entries can be restructured into a new pairincluding the other entry.

5-4: Conversion into Compatible Disks

By the way, in a writable optical disk, management of alternateaddresses is executed by using alternate-address management informationstored in the DMA recorded on the disk. That is to say, unlike the disk1 provided by the embodiment, a TDMA is not provided so that thealternate-address management information stored in the DMA itself isrenewed to keep up with an executed alternate-address process. The datastructure of the DMA recorded on a writable optical disk is the same asthe DMA recorded on the disk 1 provided by the embodiment.

In the write-once optical disk provided by the embodiment, on the otherhand, data can be written into an area including the TDMA only once sothat the embodiment must adopt a technique to update the TDMA by addingalternate-address management information to the TDMA.

Thus, in order make a disk drive for a writable optical disk capable ofreproducing data from the disk 1 provided by the embodiment, it isnecessary to reflect most recent alternate-address managementinformation recorded in the TDMA in the DMA.

In addition, in the case of a writable optical disk or the like,alternate-address information ati is recorded in the DMA for eachcluster even if an alternate-address process is carried out on clusterslocated in a contiguous area. In the case of a write-once optical disklike the one provided by the present invention, that is, in the case ofa disk with a recording capacity decreasing due to data written therein,however, it is specially important to effectively utilize the limitedarea of the TDMA. It is thus desirable to adopt a method of notincreasing the size of the TDFL even in an alternate-address processcarried out on clusters of a contiguous area. Thus, instead of includingall cluster addresses completing an alternate-address process asalternate-address information ati in the temporary defect managementinformation TDFL recorded in the TDMA, a burst-transmission formatrepresented by a pair of entries with status 1 of 0101 and status 1 of1010 as described above is adopted so as to reduce the number of piecesof recorded alternate-address information ati. That is to say, ifaddresses of three or more continuous clusters are subjected to analternate-address process, a contiguous area is allocated asalternate-address destinations for the addresses so that only twoentries of the alternate-address information ati need to be cataloged onthe TDFL.

In the case of a write-once optical disk provided by the embodiment,alternate-address information ati is cataloged on the TDFL every time analternate-address process is carried out. Thus, the size of informationcataloged on the TDFL changes. That is to say, as the number of clusterssubjected to the alternate-address process increases, the size ofinformation cataloged on the TDFL also rises. By collecting a pluralityof continuous clusters subjected to an alternate-address process into agroup of clusters dealt with by carrying out the alternate-addressprocess only once as described above, however, the increase in TDFL usedarea can be reduced.

If compatibility of the write-once optical disk implemented by theembodiment with the writable optical disk is taken into consideration,it is desirable to provide the write-once optical disk with the formatof a DFL in the DMA identical with the corresponding format in thewritable optical disk. The DFL in the DMA is obtained as a result ofconversion of a TDFL recorded in the TDMA.

To put it concretely, it is desirable to record all pieces ofalternate-address information ati in a format with status 1 set at 0000.By using such a format, it is not necessary for the disk drive to switchprocessing related to information stored in the DMA from one compatiblewith the write-once optical disk to one compatible with the writableoptical disk or vice versa so that a processing load borne by the diskdriver can be reduced.

For the reason described above, when information recorded in the TDMA istransferred to the DMA recorded on the disk 1, processing represented bya flowchart shown in FIG. 25 is carried out. It is to be noted that theinformation transferred to the DMA is final alternate-address managementinformation so that data can no longer be renewed by using the TDMA.Thus, the processing to transfer information recorded in the TDMA to theDMA recorded on the disk 1 is carried out typically as a finalize-timeprocess. In addition, the processing to transfer information recorded inthe TDMA to the DMA recorded on the disk 1 means a process to convertthe disk 1 into a disk having compatibility with a writable opticaldisk.

When the processing to transfer information recorded in the TDMA to theDMA to convert the disk 1 into a disk having compatibility with awritable optical disk is carried out, first of all, at a step F401 ofthe flowchart shown in FIG. 25, the system controller 60 carries out aprocess to transfer a TDFL and/or a space bit map from the cache memory60 a to the TDMA. Since this process is similar to the processrepresented by the flowchart shown in FIG. 22 as processing carried outat an injection time or the like, its detailed description is notrepeated.

Then, at the next step F402, the most recent TDDS recorded in the lastsector of the TDMA is read out to create information of the DDS shown inFIG. 5.

Subsequently, the flow of the processing goes on to the next step F403to determine whether or not the TDFL includes one or more pieces ofalternate-address information ati. Thus, first of all, the most recentTDFL is read out from the TDMA. As explained earlier by referring toFIG. 14, information on the recording location of the effective TDFL canbe obtained from the TDDS. The number of cataloged pieces ofalternate-address information ati can be obtained from the defect-listmanagement information of the TDFL as the number of cataloged DFLentries.

The number of cataloged pieces of alternate-address information ati setat 0 indicates that no alternate-address information ati is cataloged.In this case, the flow of the processing goes on to a step F404 at whichthe TDDS is deleted from the TDFL to leave data for creating a DFL likethe one shown in FIG. 6. This is because, as shown in FIG. 11, the TDFLincludes the TDDS.

Then, at the next step F408, the created DDS and DFL are recorded in DMA1, DMA2, DMA 3 and DMA 4, which have been allocated on the disk 1,before the execution of the processing is ended.

If the determination result obtained at the step F403 indicates that thenumber of cataloged pieces of alternate-address information ati is 1 orgreater, on the other hand, the flow of the processing goes on to a stepF405 to determine whether or not an alternate-address process has beencarried out on continuous alternate-address source and destinationareas.

At the step F405, first of all, status 1 of alternate-addressinformation ati cataloged on the TDFL as an entry is fetched.Alternate-address information ati with status 1 of 0101 indicates thatan alternate-address process has been carried out on continuousalternate-address source and destination areas represented by thealternate-address information ati.

On the other hand, all the entries cataloged on the TDFL having status 1of 0000 indicate that no alternate-address process has been carried outon continuous alternate-address source and destination areas. In thiscase, the flow of the processing goes on to a step F406 at which theTDDS is deleted from the TDFL to leave data for creating a DFL.

If an alternate-address process has been carried out on continuousalternate-address source and destination areas, first of all, at a stepF409, entries with status 1 of 0000 are copied to the DFL. These entrieseach represent alternate-address information ati for analternate-address process carried out on a normal one-to-one pairconsisting of a source cluster and a destination cluster.

Then, at the next step F410, alternate-address information ati withstatus 1 of 0101 is acquired and the alternate source address in thealternate-address information ati is saved as a start address SA. Then,alternate-address information ati following the alternate-addressinformation ati with status 1 of 0101 is acquired and the alternatesource address in the following alternate-address information ati issaved as an end address EA.

Then, at the next step F411, alternate-address information ati withstatus 1 of 0000 is cataloged on the DFL as alternate-addressinformation ati including the start address SA as the alternate sourceaddress. Subsequently, the start address SA is incremented by 1(SA=SA+1). Then, alternate-address information ati with status 1 of 0000is cataloged on the DFL as alternate-address information ati includingthe incremented start address (SA+1) as the alternate source address.These processes are carried out repeatedly till the incremented startaddress SA reaches the end address EA. By carrying out these processesrepeatedly as described above, alternate-address information atirepresenting continuous alternate-address source and destination areasis cataloged on the DFL as a plurality of entries each describingalternate-address information ati representing a normal one-to-one pairconsisting of a source cluster and a destination cluster.

Then, at the next step F412, the TDFL is searched for otheralternate-address information entry with status 1 of ‘0101’. If such anentry is found in the search, the flow of the processing goes back tothe step F410 to repeat the processes described above. That is to say,the processes of the steps F410 and F411 are carried out on all piecesof alternate-address information ati with status 1 of 0101 on the TDFL.

Then, the flow of the processing goes on from the step F406 or the stepF412 to a step F407 at which the pieces of alternate-address informationati cataloged on the created DFL are rearranged in an order ofincreasing alternate source addresses.

Then, at the next step F408, the created DDS and DFL are recorded in DMA1, DMA 2, DMA 3 and DMA 4, which have been allocated on the disk 1,before the execution of the processing is ended.

By carrying out the processing described above, alternate-addressinformation recorded in the TDMA is recorded in the DMA by convertingthe information into entries each having status 1 of 0000.

The disk drive designed for a writable optical disk reads outinformation from the DMA to verify the state of the alternate-addressprocess. Since the disk 1 provided by the embodiment is converted into adisk having a DMA created as described above, it is possible to verifythe state of the alternate-address process and carry out processing inaccordance with the state in the same way as the ordinary writableoptical disk.

6: Effects of the First TDMA Method

The disk 1 and the disk drive, which are implemented by the embodiment,have the following effects.

In accordance with the embodiment, a write request can be made more thanonce to write data at the same address in a write-once optical disk.Thus, it is possible to apply a file system, which used to be unusable,to the conventional write-once optical disk. For example, a file systemfor a variety of operating systems (OS) can be applied as it is. Anexample of such a file system is a FAT file system. In addition, datacan be exchanged without being conscious of differences in OS.

On top of that, the write-once optical disk makes it possible to renewnot only user data but, of course, directory information of the FAT orthe like recorded in the user-data area. Thus, the write-once opticaldisk provides convenience that data such as directory information of theFAT or the like can be updated from time to time.

Assuming that the AV system 120 is used, video and musical data can beutilized as updateable media as long as a free area of an ISA or an OSAremains.

In addition, an operation to record data into an address specified by ahost computer or the like as an address in the write-once optical diskor read out data from such an address is a heavy processing load for thedisk drive. If a write instruction specifying an address is received andthe address is known as an address at which data has already beenrecorded before, an error report can be returned without actually makingan access to the write-once optical disk. In order to implement such aconfiguration, it is necessary to manage the recording states of thewrite-once optical disk and, in this embodiment, a space bitmap is usedas means for implementing the management of the recording states.

By preparing a space bitmap, random recording on a write-once opticaldisk having a large storage capacity can be implemented without imposinga processing load on the disk drive. In addition, since recording statesof alternate areas can be managed, an alternate destination address usedin an alternate-address process of a defect or a logical overwritingprocess can be acquired without actually making an access to thewrite-once optical disk.

On top of that, by using the space bitmap for managingmanagement/control information areas allocated on the disk as thelead-in and the lead-out zones, recording states of themanagement/control information can also be managed. In particular, themanagement of the test area OPC serving as an area for adjusting thepower of the laser beam is effective. With the conventional technique,an access must be actually made to the disk in order to search the diskfor the address included in the OPC as an address at which data shouldbe written. It is thus quite within the bounds of possibility that anarea in which data has been recorded by using a small laser power isinterpreted as an unrecorded area. By using the space bitmap for alsomanaging the OPC area, however, it is possible to avoid suchmisinterpretation.

By combining the overwrite function described before with the spacebitmap, the processing load borne by the disk drive can be reduced. Thatis to say, as is obvious from the pieces of processing represented bythe flowcharts shown in FIGS. 17 to 21, without actually making anaccess to the disk, it is possible to determine whether or not theoverwrite function is to be activated.

In addition, by putting a defective area detected at a write time andsurroundings of the area in recorded status in the space bitmap, it ispossible to eliminate a time-consuming process to record data at adefective address caused by an injury. In addition, by combining thisfeature of the space bitmap and the overwrite function, it is possibleto carry out a write process, which appears to the host as a processhaving no write error.

On top of that, an updated TDML serving as alternate address managementinformation and an updated space bitmap are additionally recorded in theTDMA and, at the same time, information indicating the effective TDFLand/or the effective space bitmap is also recorded as well. Thus, theeffective TDFL and/or the effective space bitmap can be identified ateach point of time. That is to say, the disk drive is capable ofcorrectly grasping the updating state of the alternate-addressmanagement information.

In addition, the fact that the space bitmap is recorded in the TDMAmeans that the data zone serving as a main area for recording the spacebit map is not used. For example, the ISA or the like is not used. Thus,it is possible to carry out an alternate-address process effectivelyutilizing a data zone and any one of an ISA and an OSA, which each serveas an alternate-address area. For example, either an ISA or an OSA isselected as an alternate-address area to be used in an alternate-addressprocess typically on the basis of preference of an area closer to thealternate source address. By selecting either an ISA or an OSA in thisway, an operation to make an access to data completing thealternate-address process can be made efficient.

On top of that, in an operation to write data onto the disk 1, data maynot be written into a specified area due to a defect detected in thearea and, if data is received continuously thereafter, by carrying outan alternate-address process, the write operation can be continuedwithout returning an error report. For clarity, refer to the flowchartsshown in FIGS. 17 and 18.

In addition, if an operation to write data into a specified area cannotbe carried out due to a defect detected in the area, in many cases,areas surrounding the defective area are most likely also areas intowhich data cannot be recorded. In this case, a write process can becarried out as a process assuming that predetermined areas following thedefective area are also defective areas to which no access is actuallymade. If data for these areas has already been received by the diskdrive, an alternate-address process can be carried out on the areas. Inthis case, even if three or more continuous clusters are subjected to analternate-address process, alternate-address information ati can becataloged on the TDFL only as two entries so that the size of the usedwrite area can be reduced.

On top of that, by carrying out a process on the space bitmap to treat aprocessed area as an area, in which data has been written in this way,an illegal access can be avoided.

If no data for areas following an area, in which data cannot be written,has been received by the disk drive, on the other hand, predeterminedones of the following areas are cataloged on the TDFL as defectiveclusters each having an allocated alternate destination and treated onthe space bitmap as areas, in which data has already been written. If aninstruction to write data into such an area is received from the hostthereafter, the disk drive refers to the space bitmap to find out thatthe area is an area, in which data has already been written. In thiscase, the overwrite function can be executed to record the data withoutgenerating an error.

In addition, since the DMA has the same data structure as the writabledisk, data can be reproduced by a reproduction system from the diskprovided by the embodiment even if the reproduction system designed fora writable disk is used.

7: Second TDMA Method

7-1: TDMAs

Next, a second TDMA method is explained. It is to be noted that,basically, the second TDMA method has a number of similarities to thefirst one described so far. Thus, only differences between the twomethods are mainly explained.

The structure of the disks are the same as those shown in FIGS. 1 to 3.In addition, the data structures of the DMA are also the same as thoseshown in FIGS. 4 to 8.

However, the second TDMA method is different from the first one in that,in the case of the second TDMA method, a space bitmap is not recorded inthe TDMA. Instead, a space bitmap is recorded in the ISA.

The data structure of the TDMA is shown in FIG. 26. The size of the TDMAis 2,048 clusters. One to four clusters identified by cluster numbers 1to 4 are used as clusters for recording a TDFL (temporary defect list).

A cluster identified by cluster number n is used as a cluster forrecording a TDDS (temporary disk definition structure), which isdetailed information on the optical recording medium.

In the TDMA, the TDFL and the TDDS are recorded as a set. If an updatedset is additionally recorded in the TDMA, the set is written at thebeginning of a free area in the TDMA. That is to say, the updated set isrecorded in an area immediately following a recorded TDDS.

Not shown in a figure, the data structure of the TDFL having a size inthe range one to four bytes is all but the same as that shown in FIG.11. In the case of the second TDMA method, however, unlike the firstmethod, a TDDS is not recorded in the last sector of the TDFL. That isto say, the area following the alternate-address information atiterminator as shown in FIG. 11 is all filled up with codes of 00h. Thus,the TDDS is recorded in a cluster different from the clusters used forrecording the TDFL as shown in FIG. 26.

The data structure of the defect-list management information included inthe TDFL is exactly the same as that shown in FIG. 7. In addition, thedata structure of the alternate-address information ati is entirelyidentical with that shown in FIG. 8. A pair of pieces ofalternate-address information ati with values of status 1 set at 0101and 1010 is interpreted as a pair of entries representing a plurality ofcontinuous clusters serving as an alternate source and a plurality ofcontinuous clusters serving as an alternate destination.

FIG. 27 is a diagram showing the data structure of the TDDS, which isrecorded in a cluster other than clusters for recording the TDFL. Inthis case, the size of the TDDS is one cluster, which is the same as theDDS shown in FIG. 5. The contents of the TDDS are all but the same asthose explained before by referring to FIG. 5. As is obvious fromcomparison of the data structures shown in FIGS. 5 and 27, however,bytes starting with a byte at byte position 4 are bytes used forrecording the sequence number of the TDDS, bytes starting with a byte atbyte position 16 are bytes used for recording the physical address ofthe first sector in a drive area inside the TDMA and bytes starting witha byte at byte position 24 are bytes used for recording the physicaladdress AD_DFL of the first sector in the TDFL inside the TDMA.

It is to be noted that, in the case of a two-layer disk, a TDMA isprovided for each of layers 0 and 1. Much like the first TDMA methoddescribed above, it is possible to adopt a TDMA-utilizing techniquewhereby, first, the TDMA provided for layer 0 is used as a TDMA forupdating the TDFL and the TDDS and, as the TDMA provided for layer 0 isused up entirely, the TDMA provided for layer 1 is used.

7-2: ISAs and OSAs

FIG. 28 is a diagram showing an ISA and an OSA. In the case of thisembodiment, only the OSA is used as an alternate area. The ISA is usedas an area for recording space bitmaps.

The sizes of the ISA and the OSA are defined in the DDS and the TDDS.The size of the ISA is determined at an initialization time and remainsconstant thereafter. However, the size of the OSA can be changed evenafter data is recorded in the OSA.

When recording data into the OSA in an alternate-address process, thedata is written in an area starting with the last cluster of the OSA ina direction toward the cluster at the beginning of the OSA withoutskipping any clusters located between the last and the beginningclusters.

The ISA is used one cluster after another starting with the cluster atthe beginning of the ISA as an area for recording space bitmaps SBM#1 toSBM#5 as shown in the figure. To put it in detail, much like the firstTDMA method described earlier, the size of a space bitmap is one clusterand the first space bitmap is recorded in the first cluster. When thespace bitmap is updated thereafter, the updated space bitmap is recordedas a new bitmap at the beginning of the free area of the ISA, that is,in the area immediately succeeding the last recorded space bitmap,without creating a free space between the last recorded space bitmap andthe new space bitmap.

Thus, the last space bitmap among bitmaps recorded in the ISA becomesthe effective information. In the case of the ISA shown in FIG. 28,space bitmap SBM#5 is the effective information.

The data structure of the space bitmap is all but the same as that shownin FIG. 10 except that, in the case of the space bitmap for the secondTDMA method, unlike the data structure shown in FIG. 10, the last sectoris not used as a sector for recording a TDDS.

It is to be noted that, in the case of a two-layer disk, a space bitmapprovided for layer 0 is recorded in the ISA for layer 0 while a spacebitmap provided for layer 1 is recorded in the ISA for layer 1.

However, the ISA for layer 0 and the ISA for layer 1 can be regarded asa single area with a large size without regard to whether the spacebitmap is a bitmap provided for layer 0 or 1. In this case, the ISA oflayer 0 is first used as an area for storing space bitmaps provided forboth layers and, as the ISA of layer 0 is used up entirely, the ISA oflayer 1 is used.

By the way, when a disk 1 provided by this embodiment as a disk with anISA thereof used for recording space bitmaps is mounted on another diskdrive, it is necessary to prevent the ISA from being used inadvertentlyas an alternate area. In order to prevent such an ISA from being usedinadvertently as an alternate area, spare area full flags of the TDDSshown in FIG. 27 are used.

In the case of a one-layer disk, the spare area full flags having a sizeof 1 byte has a format shown in FIG. 29A. In the case of a two-layerdisk, on the other hand, the spare area full flags having a size of 1byte has a format shown in FIG. 29B.

First of all, in the case of a one-layer disk shown in FIG. 29A, bits b7to b2 are reserved. A bit b1 is an outer spare area full flag. A valueof 1 is set in this outer spare area full flag to indicate that thewhole OSA has been filled up with data recorded therein. A bit b0 is aninner spare area full flag. A value of 1 is set in this inner spare areafull flag to indicate that the whole ISA has been filled up with datarecorded therein.

In the case of a two-layer disk shown in FIG. 29B, on the other hand, inaddition to bits b1 and b0 of a one-layer disk, bits b2 and b3 arerespectively an OSA full flag and ISA full flag of the second layer. Inthis case, bits b0 and b1 are respectively an OSA full flag and ISA fullflag of the first layer.

Thus, if a space bitmap is recorded in an ISA as is the case with thisembodiment, the inner spare area full flag provided for the ISA is setat 1. By doing so, since the disk 1 appears to another disk drive as adisk with no free area left in the ISA, the other disk drive can beprevented from using the ISA for an alternate-address process.

8: Operations for the Second TDMA Method

8-1: Data Writing

In the case of the second TDMA method, the system controller 60 carriesout data-writing processing represented by a flowchart shown in FIG. 30.

Also in the case of the second TDMA method, it is assumed that, at apoint of time the data-writing processing described below is about to becarried out, the disk 1 has been mounted on the disk drive and a TDFL, aTDDS and a space bitmap have been transferred from the TDMA recorded onthe mounted disk 1 to the cache memory 60 a. In addition, explanation ofa process to convert a logical address into a physical address from timeto time is also omitted from the following description.

Let the system controller 60 receive a request to write data at acertain address from a host apparatus such as the AV system 120. In thiscase, the system controller 60 starts the processing represented by theflowchart shown in FIG. 30. The flowchart begins with a step F501 atwhich the system controller 60 refers to the space bitmap stored in thecache memory 60 a (or the recent bitmap updated in the cache memory 60a) to determine whether or not data has been recorded at the addressspecified in the write request.

If no data has been recorded at the specified address, the flow of theprocessing goes on from the step F502 to a step F503, at which a normalwrite process is carried out to execute a command to write data at theaddress.

That is to say, at the F503, the system controller 60 executes controlto write data at the specified address. In other words, the opticalpickup 51 is driven to make an access to the specified address andrecord the data to be written as requested at the specified address.

As the data-writing process is normally ended, the flow of theprocessing goes on to a step F504 at which a space bitmap stored in thecache memory 60 a is updated. That is to say, a bit allocated in thespace bitmap to a cluster in which the data has been written is set at avalue indicating that data has been written in the cluster. Then, theexecution of the processing carried out in response to the write requestis ended.

If an error is generated in the course of the write processing due to,among other causes, an injury on the disk 1, an alternate-addressprocess may be carried out in some cases. In this case, analternate-address process like the one explained earlier by referring tothe flowchart shown in FIG. 18 is carried out. It is to be noted that astep to carry out this alternate-address process is not included in thedescription of the flowchart shown in FIG. 30.

If the determination result obtained at the step F502 reveals a spacebitmap indicating that data has been recorded at the address specifiedin the write request received from the host apparatus, on the otherhand, the flow of the processing goes on to a step F505. At this step,the system controller 60 determines whether or not the function to renewdata is effective. It is to be noted that a function to enable thefunction to renew data will be explained later by referring to aflowchart shown in FIG. 31.

If the function to renew data is not effective, the flow of theprocessing goes on to a step F506 at which an error report is returnedto the host apparatus before the execution of the processing is ended.

If the function to renew data is effective, on the other hand, the flowof the processing goes on to a step F507 to determine first of allwhether or not an alternate-address process for renewing data can beactually carried out.

In order to carry out the alternate-address process, the spare area OSAmust have a free area for at least recording the data requested in thewrite operation. In addition, the TDMA must have a margin allowing anentry of the alternate-address information ati for managing thisalternate-address process to be added, that is, allowing the TDFL to beupdated.

If the OSA has a free area and the TDMA has a margin allowing an entryof the alternate-address information ati for managing thisalternate-address process to be added, the flow of the processingcarried out by the system controller 60 goes on from the step F507 to astep F508 at which the optical pickup 51 is driven to make an access tothe OSA and record the data to be written as requested this time in theOSA.

Then, at the next step F509, the space bitmap stored in the cache memory60 a is updated. That is to say, a bit allocated in the space bitmap toan OSA cluster including an address at which the data has been writtenin an alternate-address process carried out to renew data is set at avalue indicating that data has been written in the cluster.

Subsequently, at the next step F510, the TDFL stored in the cache memory60 a is updated. That is to say, alternate-address information atirepresenting the alternate-address process carried out this time isnewly added as an entry to the TDFL. As an alternative, ifalternate-address information ati including the same alternate sourceaddress as the address specified in the write request already exists asan entry in the TDFL, this entry is renewed. In addition, an entry countincluded in the defect-list management information as a countrepresenting the number of cataloged DFL entries is incremented in casealternate-address information ati is newly added to the TDFL, and thenumber of unused OSA clusters is decremented. Then, the execution of theprocessing carried out in response to the write request is ended.

By carrying out the processing to use the OSA as described above, thesystem controller 60 is capable of coping with a request to write datainto an address, at which data has already been recorded before, thatis, coping with a request to renew data.

If the determination result obtained at the step F507 indicates that theOSA does not have a free area for at least recording the data requestedin the write operation or the TDMA does not have a margin allowing anentry of the alternate-address information ati for managing thisalternate-address process to be added, on the other hand, analternate-address process cannot be carried out. In this case, the flowof the processing goes on to a step F511 at which an error reportindicating that there is no area for writing the data is returned to thehost apparatus before the execution of the processing is ended.

It is to be noted that alternate-address information ati can be newlygenerated at the step F510 to reflect the executed alternate-addressprocess by carrying out the processing represented by the flowchartshown in FIG. 20.

It is also worth noting that, if the ISA used as an area for recording aspace bitmap does not include a free area, a recording operation forupdating the space bitmap cannot be carried out. In this case, thefollowing typical countermeasures can be taken to allow a process ofrecording user data to be carried out:

-   -   When a disk with the ISA thereof including recorded space        bitmaps but having no left free area is mounted on the disk        drive, the disk drive checks an RF signal serving as a        reproduced-data signal for a free area available on the disk on        the basis of the most recent space bitmap and reconstructs the        space bitmaps.    -   For a disk with the ISA thereof including recorded space bitmaps        but having no left free area, the disk drive allows only limited        write operations (or sequential write operations) to be carried        out to record data in an area following the last address of        recorded user data.

By the way, in the case of the present embodiment, the ISA is used as aspare area for recording space bitmaps. Thus, it is necessary to makethe data renewal function effective or ineffective in dependence onwhether or not the disk 1 mounted on the disk drive is a disk allowingthe ISA to be used as a spare area for recording space bitmaps.

At the step F505, the system controller 60 determines whether or not thefunction to renew data has been put in effective status, which is set bythe processing represented by the flowchart shown in FIG. 31.

The processing to set the data renewal function as represented by theflowchart shown in FIG. 31 is carried out typically when the disk 1 ismounted on the disk drive.

When the disk 1 is mounted on the disk drive, the system controller 60checks the TDDS of the disk 1 to examine bit b0 of the spare area fullflags provided at byte position 52 at a step F601.

As described earlier by referring to FIGS. 29A and 29B, in the disk 1provided by the present embodiment as a disk including the ISA used asan area for recording space bitmaps, bit b0 is set at 1. Even in thecase of a disk including the ISA used as an alternate area, bit b0 isset at 1 as the entire ISA is used up. That is to say, at least, if thedisk is a disk provided by the present embodiment, bit b0 is set at 1and, if the disk is not a disk provided by the present embodiment, bitb0 is set at 0 or 1. Thus, at least, if bit b0 is set at 0, the disk isnot a disk provided by the present embodiment.

Thus, if bit b0 is set at 0, the flow of the processing goes on to astep F604 at which the function to renew data is turned off.

In this case, the disk drive is not capable of carrying out analternate-address process and a process to record a space bitmap on thisdisk. That is to say, the steps F507 to F511 of the flowchart shown inFIG. 30 are not executed. In addition, the step F504 of the flowchartshown in FIG. 30 to update a space bitmap for the case of an ordinarywrite operation is also not executed. However, details of operations fora disk not provided by the present embodiment are not explicitlyincluded in the flowchart shown in FIG. 30.

Thus, the data renewal operation of the present embodiment is notcarried out even though the state of the ISA and the reproductioncompatibility are maintained.

If the examination result obtained at the step F601 indicates that bitb0 is 1, on the other hand, the flow of the processing goes on to a stepF602 at which the last cluster of the ISA is examined. This is becauseit is quite within the bounds of possibility that the disk mounted onthe disk drive is the disk provided by the present embodiment.

If the last cluster of the ISA is a cluster for recording a spacebitmap, the flow of the processing goes on from the step F603 to a stepF605 to read out the space bitmap and store the bitmap in the cachememory 60 a. Then, at the next step F606, the function for renewing datais made effective.

If the examination result obtained at the step F603 reveals that thelast cluster of the ISA is determined to be not a cluster for recordinga space bitmap, on the other hand, the flow of the processing goes on tothe step F604 at which the function to renew data is made ineffective.

By carrying out the processing to set the status of the data renewalfunction described above, the function to renew data is made effectivefor a disk provided by the present invention as a disk including an ISAas an area for recording a space bitmap. In the case of a disk using theISA as an alternate area, on the other hand, the ISA is not used as anarea for recording a space bitmap and the data renewal function providedby the present embodiment is not made effective either. An example ofthe disk using the ISA as an alternate area is a disk containing datarecorded by another disk drive.

8-2: Data Fetching

By referring to a flowchart shown in FIG. 32, the following descriptionexplains processing carried out by the system controller 60 employed inthe disk drive to reproduce data from the disk 1 at a reproduction time.

Assume that the system controller 60 receives a request specifying anaddress in the disk 1 to read out data recorded at the address from ahost apparatus such as the AV system 120.

In this case, the system controller 60 carries out the processingstarting at a flowchart step F701 at which the space bitmap is referredto in order to determine whether or not data has been recorded in theaddress specified in the request.

If no data has been recorded in the address specified in the request,the flow of the processing goes on to a step F702 at which an errorreport indicating that the specified address is an incorrect address isreturned to the host apparatus, and the execution of the processing isended.

If data has been recorded in the address specified in the request, onthe other hand, the flow of the processing goes on to a step F703 atwhich the TDFL is searched for alternate-address information atiincluding an alternate source address matching the address specified inthe request.

If no alternate-address information ati including an alternate sourceaddress matching the address specified in the request was found in thesearch, the flow of the processing goes on from the step F703 to a stepF704 at which the data is reproduced from the specified address beforethe execution of the processing is ended. This completed processing is anormal reproduction process to reproduce data from the user-data area.

If the search result obtained at the step F703 indicates that there isalternate-address information ati including an alternate source addressmatching the address specified in the request, on the other hand, theflow of the processing goes on from the step F703 to a step F705 atwhich an alternate source address is extracted from thealternate-address information ati. That is to say, an address in the OSAis acquired.

Then, at the next step F706, the system controller 60 executes controlto read out the data from the acquired address in the OSA or thealternate source address extracted from the alternate-addressinformation ati, and transfer the reproduced data to the host apparatussuch as the AV system 120 before ending the execution of the processing.

By carrying out the processing described above, most recent data can becorrectly reproduced and transferred to the host apparatus in responseto even a data reproduction request made by the host after renewal ofthe data.

8-3: Updating of the TDFL/Space Bitmap and Conversion into CompatibleDisks

Much like the first TDMA method described before, an updated TDFL andspace bitmap are transferred from the cache memory 60 a to the disk 1 ata predetermined point of time such as the time the disk 1 is ejectedfrom the disk drive.

In the case of the second TDMA method, alternate-address managementinformation (including the TDFL and the TDDS) as well as a space bitmapare transferred from the cache memory 60 a to the disk 1 in processingrepresented by a flowchart shown in FIG. 33.

The flowchart begins with a step F801 at which the system controller 60determines whether or not the TDFL stored in the cache memory 60 a hasbeen updated. If the TDFL stored in the cache memory 60 a has beenupdated, the flow of the processing goes on to a step F802 at which theTDFL is recorded at the beginning of a free area in the TDMA recorded onthe disk 1.

Then, at the next step F803, the TDDS is recorded at the beginning of afree area in the TDMA recorded on the disk 1.

It is to be noted that, when the TDFL and the TDDS are recorded in theTDMA, the space bitmap stored in the cache memory 60 a may need to beupdated to reflect the recording.

At a step F804, the space bitmap stored in the cache memory 60 a isexamined to determine whether or not the bitmap has been updated.

If the space bitmap stored in the cache memory 60 a has been updated,the flow of the processing goes on to a step F805 at which the spacebitmap is transferred from the cache memory 60 a to the beginning of afree area in the ISA recorded on the disk 1.

As described above, the TDFL and the TDDS are recorded in the TDMAwhereas the space bitmap is recorded in the ISA so thatalternate-address information and information indicating whether or notdata has been recorded in each cluster are reflected in the disk 1.

In addition, the TDFL and the TDDS are updated in the TDMA but, in orderto maintain reproduction compatibility with writable disks, informationrecorded in the TDMA is transferred to the DMA at a finalize time. Atthat time, the most recent TDFL and the most recent TDDS are recorded inthe DMA. However, it is necessary to convert all pieces ofalternate-address information ati with status 1 other than 0000 intopieces of alternate-address information ati with status 1 of 0000 bycarrying out the processes of the steps F405 to F407 of the flowchartshown in FIG. 25.

9: Effects for the Second TDMA Method

Even by adopting the second TDMA method described above, basically, thesame effects as the first TDMA method can be obtained.

In the case of the present embodiment, space bitmaps are stored in theISA. Since the disk layout is not changed, however, the presentembodiment is good from the standpoint of compatibility with existingdisks.

In addition, for the ISA used as an area for recording space bitmaps,the spare area full flag is set at 1 so as to prevent-another disk drivefrom using the ISA as an alternate area.

Since no space bitmaps are recorded in the TDMA, the TDMA can be usedeffectively as an area for updating the TDFL and the TDDS. That is tosay, the alternate-address management information can be updated moretimes to keep up with a larger number of data renewals.

Disks provided by preferred embodiments and disk drives designed for thedisks have been described so far. However, the scope of the presentinvention is not limited to the preferred embodiments. That is to say, avariety of modifications within the range of essentials of the presentinvention are conceivable.

For example, as a recording medium of the present invention, a recordingmedium other than the optical-disk medium can be used. Examples of therecording medium other than the optical-disk medium are amagneto-optical disk, a magnetic disk and media based on a semiconductormemory.

As is obvious from the above descriptions, the present invention has thefollowing effects.

In accordance with the present invention, a write-once recording mediumcan be used virtually as a recording medium allowing data alreadyrecorded thereon to be renewed. Thus, a file system such as a FAT filesystem for a writable recording medium can be used for a write-oncerecording medium. As a result, the present invention provides an effectthat the usefulness of a write-once recording medium can be enhancedconsiderably. For example, the FAT file system, which is a standard filesystem for information-processing apparatus such as a personal computer,allows a variety of operating systems (OS) to reproduce data from awritable recording medium and record data onto only a writable recordingmedium. By virtue of the present invention, however, the FAT file systemcan also be applied to a write-once recording medium as it is and allowsdata to be exchanged without being conscious of differences betweenoperating systems. These features are also good fromcompatibility-maintenance point of view.

In addition, in accordance with the present invention, a write-oncerecording medium can be used as a writable recording medium as long asan alternate area and an area for updating alternate-address managementinformation remain in the write-once recording medium. Thus, thewrite-once recording medium can be used effectively. As a result, thepresent invention provides an effect that resource wasting can bereduced.

On top of that, a space bitmap can be referred to as informationindicating whether or not data has been recorded in any cluster, whichis used as a data unit, on the recording medium. In general, a hostcomputer or the like makes a request to record data at an addressspecified in the request as an address in a recording medium mounted ona recording apparatus or a request to reproduce data from an addressspecified in the request as an address in a recording medium mounted ona reproduction apparatus, and such requests are a heavy processing loadthat must be borne by the recording and reproduction apparatus. Byreferring to such a space bitmap, however, it is possible to determinewhether or not data has already been recorded at an address specifiedfor example in a write request. If data has already been recorded at thespecified address, an error report can be returned to the host computerwithout actually making an access to the recording medium. As analternative, the data can be renewed by carrying out analternate-address process. In particular, it is also possible todetermine whether or not the function to renew data is effective(enabled) without actually making an access to the recording medium.

In addition, by referring to such a space bitmap, it is possible todetermine whether or not data has already been recorded at an addressspecified for example in a read request. If no data has already beenrecorded at the specified address, an error report can be returned tothe host computer without actually making an access to the recordingmedium.

That is to say, it is possible to reduce a processing load borne by therecording and reproduction apparatus in respectively recording andreproducing data onto and from the recording medium by making randomaccesses to the recording medium.

In addition, by using the information indicating whether or not data hasbeen recorded in any cluster, recording states of alternate areas can bemanaged. Thus, it is possible to acquire an alternate destinationaddress, which is to be used in an alternate-address process carried outdue to the existence of a defect or carried out to renew data, withoutactually making an access to the recording medium.

On top of that, management/control areas such as the lead-in andlead-out areas can also be managed by using the information indicatingwhether or not data has been recorded in any cluster. Thus, theinformation indicating whether or not data has been recorded in anycluster is suitable for typically a process to grasp the used range ofthe OPC for adjusting a laser power or the like. That is to say, whenthe OPC is searched for a trial-write area for adjusting a laser power,it is not necessary to actually make an access to the recording mediumand it is also possible to avoid incorrect detection as to whether ornot data has been recorded in a cluster.

In addition, if the information indicating whether or not data has beenrecorded in any cluster reveals that an area used as a target of a writeoperation is defective due to an injury and data has been recorded inareas surrounding the target area, it is possible to eliminate a processfor recording data at an address in the defective target area as aprocess that would otherwise take long time to carry out. On top ofthat, by combining this function with a function to renew data, it ispossible to carry out a write process, which appears to the host as aprocess involving no write error.

In addition, in a process to update alternate-address managementinformation, alternate-address management information is additionallyrecorded in the second alternate-address management information area ofthe recording medium, and information indicating effectivealternate-address management information is also recorded. In this way,effective alternate-address management information in the secondalternate-address management information area can be identified. That isto say, a recording or reproduction apparatus is capable of correctlygrasping the updating state of the alternate-address managementinformation at every point of time.

On top of that, in accordance with a data-writing process, a spacebitmap serving as written/unwritten state indication information is alsoadditionally recorded in the second alternate-address managementinformation area of the recording medium and information indicatingeffective written/unwritten state indication information is recorded aswell. Thus, effective written/unwritten state indication information canbe identified correctly.

In addition, in this case, the written/unwritten state indicationinformation is not recorded in a main data area. Thus, analternate-address process effectively using an alternate-address area inthe main data area can be carried out, and an operation to make anaccess to the data recorded by carrying out the alternate-addressprocess can be made more efficient.

If the space bitmap serving as the written/unwritten state indicationinformation is recorded in the main data area, on the other hand, thesecond alternate-address management information area can be utilizedeffectively as an area for updating alternate-address managementinformation. That is to say, the number of times alternate-addressmanagement information is updated can be increased so that data can berenewed more times.

If the written/unwritten state indication information is recorded in aportion (such as the ISA) of an alternate-address area in the main dataarea, information is recorded as information indicating that the portionof the alternate-address area cannot be used for an alternate-addressprocess. Thus, another recording/reproduction apparatus can be preventedfrom using the portion of the alternate-address area. As a result, anincorrect operation can be avoided. In addition, in the case of therecording apparatus provided by the present invention, if informationexists as information indicating that the portion of thealternate-address area cannot be used for an alternate-address process,the data recorded in the portion of the alternate-address area is readout to determine whether or not data can be renewed. Thus, an incorrectoperation can be avoided. As a result, the present invention provides aneffect of maintaining compatibility with another recording/reproductionapparatus.

1. A recording medium provided with a write-once area allowing data tobe recorded therein once and comprising a main data area as well as amanagement/control area for recording management/control information forrecording data into said main data area and reproducing data from saidmain data area wherein: said main data area comprises a regularrecording/reproduction area which data is recorded into and reproducedfrom as well as an alternate area for recording data due to a defectexisting in said regular recording/reproduction area or for recordingdata in a process to renew data; said management/control area comprisesa first alternate-address management information area for recordingfirst alternate-address management information for managingalternate-address processes using said alternate area and a secondalternate-address management information area for recording saidalternate-address management information in an updateable state; andsaid main data area or said management/control area is used forrecording written/unwritten state indication information for each dataunit of said main data area and each data unit of saidmanagement/control area as information indicating whether or not datahas been written into said data unit.
 2. The recording medium accordingto claim 1 wherein, in accordance with said alternate-address process,alternate-address management information is additionally recorded insaid second alternate-address management information area andinformation indicating effective alternate-address managementinformation is also recorded.
 3. The recording medium according to claim1 wherein, in accordance with a data-writing process, saidwritten/unwritten state indication information is additionally recordedin said second alternate-address management information area andinformation indicating effective alternate-address managementinformation is also recorded.
 4. The recording medium according to claim1 wherein a written/unwritten state indication information area forrecording said written/unwritten state indication information isprovided in said main data area, in accordance with a data-writingprocess, said written/unwritten state indication information isadditionally recorded in said written/unwritten state indicationinformation area and last written/unwritten state indication informationin said written/unwritten state indication information area is madeeffective.
 5. The recording medium according to claim 4 wherein aportion in an alternate area of said main data area is used as saidwritten/unwritten state indication information area, and information isrecorded to indicate that said portion of said alternate area is used assaid written/unwritten state indication information area and, hence,cannot serve as an area used for said alternate-address process.
 6. Arecording apparatus provided for a recording medium provided with awrite-once area allowing data to be recorded therein once and comprisinga main data area as well as a management/control area for recordingmanagement/control information for recording data into said main dataarea and reproducing data from said main data area wherein: said maindata area comprises a regular recording/reproduction area which data isrecorded into and reproduced from as well as an alternate area forrecording data due to a defect existing in said regularrecording/reproduction area or for recording data in a process to renewdata; said management/control area comprises a first alternate-addressmanagement information area for recording first alternate-addressmanagement information for managing alternate-address process using saidalternate area and a second alternate-address management informationarea for recording said alternate-address management information in anupdateable state; and said main data area or said management/controlarea is used for recording written/unwritten state indicationinformation for each data unit of said main data area and each data unitof said management/control area as information indicating whether or notdata has been written into said data unit, said recording apparatuscomprising: write means for writing data onto said recording medium;confirmation means for determining whether or not data has been recordedat an address related to a data-writing request to write data in saidmain data area on the basis of said written/unwritten state indicationinformation; determination means for determining whether or not analternate-address process using said alternate area as well as saidsecond alternate-address management information area can be carried out;and write control means for controlling said write means to write dataat said address related to said data-writing request and updating saidwritten/unwritten state indication information if said confirmationmeans determines that data has not been recorded at said address relatedto said data-writing request but controlling said write means to writedata related to said data-writing request in said alternate area as wellas updating said alternate-address management information and saidwritten/unwritten state indication information if said confirmationmeans determines that data has been recorded at said address related tosaid data-writing request whereas said determination means determinesthat said alternate-address process can be carried out.
 7. The recordingapparatus according to claim 6 wherein said write control means updatessaid alternate-address management information by additionally recordingalternate-address management information in said secondalternate-address management information area of said recording mediumand recording information indicating effective alternate-addressmanagement information.
 8. The recording apparatus according to claim 6wherein said write control means updates said written/unwritten stateindication information by additionally recording said written/unwrittenstate indication information in said second alternate-address managementinformation area of said recording medium and recording informationindicating effective written/unwritten state indication information. 9.The recording apparatus according to claim 6 wherein said write controlmeans updates said written/unwritten state indication information byadditionally recording written/unwritten state indication information insaid main data area of said recording medium.
 10. The recordingapparatus according to claim 9, said apparatus further comprising setmeans for setting an indicator as to whether or not data can be renewedon the basis of information recorded on said recording medium asinformation indicating that said portion of said alternate area in saidmain data area of said recording medium is used as saidwritten/unwritten state indication information area and, hence, cannotserve as an area used for said alternate-address process and on thebasis of the substance of data recorded in said portion existing in saidalternate area as said written/unwritten state indication informationarea in a configuration wherein said write control means uses saidportion of said alternate area as said written/unwritten stateindication information area and additionally records saidwritten/unwritten state indication information in said written/unwrittenstate indication information area.
 11. A reproduction apparatus providedfor a recording medium provided with a write-once area allowing data tobe recorded therein once and comprising a main data area as well as amanagement/control area for recording management/control information forrecording data into said main data area and reproducing data from saidmain data area wherein: said main data area comprises a regularrecording/reproduction area which data is recorded into and reproducedfrom as well as an alternate area for recording data due to a defectexisting in said regular recording/reproduction area or for recordingdata in a process to renew data; said management/control area comprisesa first alternate-address management information area for recordingfirst alternate-address management information for managingalternate-address process using said alternate area and a secondalternate-address management information area for recording saidalternate-address management information in an updateable state; andsaid main data area or said management/control area is used forrecording written/unwritten state indication information for each dataunit of said main data area and each data unit of saidmanagement/control area as information indicating whether or not datahas been written into said data unit, said reproduction apparatuscomprising: read means for reading out data from said recording medium;first confirmation means for determining whether or not data has beenrecorded at an address related to a read request to read out data fromsaid main data area on the basis of said written/unwritten stateindication information; second confirmation means for determiningwhether or not said address related to said read request to read outdata from said main data area is an address completing analternate-address process on the basis of said alternate-addressmanagement information; and read control means for controlling said readmeans to read out data from said address related to said read request ifsaid first confirmation means determines that data has been recorded atsaid address related to said read request and said second confirmationmeans determines that said address related to said read request is notan address completing an alternate-address process, but controlling saidread means to read out data related to said read request from saidalternate area on the basis of said alternate-address managementinformation if said first confirmation means determines that data hasbeen recorded at said address related to said read request and saidsecond confirmation means determines that said address related to saidread request is an address completing an alternate-address process. 12.A recording method provided for a recording medium provided with awrite-once area allowing data to be recorded therein once and comprisinga main data area as well as a management/control area for recordingmanagement/control information for recording data into said main dataarea and reproducing data from said main data area wherein: said maindata area comprises a regular recording/reproduction area which data isrecorded into and reproduced from as well as an alternate area forrecording data due to a defect existing in said regularrecording/reproduction area or for recording data in a process to renewdata; said management/control area comprises a first alternate-addressmanagement information area for recording first alternate-addressmanagement information for managing alternate-address process using saidalternate area and a second alternate-address management informationarea for recording said alternate-address management information in anupdateable state; and said main data area or said management/controlarea is used for recording written/unwritten state indicationinformation for each data unit of said main data area and each data unitof said management/control area as information indicating whether or notdata has been written into said data unit, said recording methodcomprising: a confirmation step of determining whether or not data hasbeen recorded at an address related to a data-writing request to writedata in said main data area on the basis of said written/unwritten stateindication information; a determination step of determining whether ornot an alternate-address process using said alternate area and saidsecond alternate-address management information area can be carried out;a first write step of writing data at said address related to saiddata-writing request and updating said written/unwritten stateindication information if a determination result obtained at saidconfirmation step indicates that data has not been recorded at saidaddress related to said data-writing request; and a second write step ofwriting data related to said data-writing request in said alternate areaas well as updating said alternate-address management information andsaid written/unwritten state indication information if a determinationresult obtained at said confirmation step indicates that data has beenrecorded at said address related to said data-writing request whereas adetermination result obtained at said determination step indicates thatsaid alternate-address process can be carried out.
 13. A reproductionmethod provided for a recording medium provided with a write-once areaallowing data to be recorded therein once and comprising a main dataarea as well as a management/control area for recordingmanagement/control information for recording data into said main dataarea and reproducing data from said main data area wherein: said maindata area comprises a regular recording/reproduction area which data isrecorded into and reproduced from as well as an alternate area forrecording data due to a defect existing in said regularrecording/reproduction area or for recording data in a process to renewdata; said management/control area comprises a first alternate-addressmanagement information area for recording first alternate-addressmanagement information for managing alternate-address process using saidalternate area and a second alternate-address management informationarea for recording said alternate-address management information in anupdateable state; and said main data area or said management/controlarea is used for recording written/unwritten state indicationinformation for each data unit of said main data area and each data unitof said management/control area as information indicating whether or notdata has been written into said data unit, said reproduction methodcomprising: a first confirmation step of determining whether or not datahas been recorded at an address related to a read request to read outdata from said main data area on the basis of said written/unwrittenstate indication information; a second confirmation step of determiningwhether or not said address related to said read request to read outdata from said main data area is an address completing analternate-address process on the basis of said alternate-addressmanagement information; a first read step of reading out data from saidaddress related to said read request if a determination result obtainedat said first confirmation step indicates that data has been recorded atsaid address related to said read request and a determination resultobtained at said second confirmation step indicates that said addressrelated to said read request is not an address completing analternate-address process; and a second read step of reading out datarelated to said read request from said alternate area on the basis ofsaid alternate-address management information if a determination resultobtained at said first confirmation step indicates that data has beenrecorded at said address related to said read request and adetermination result obtained at said second confirmation step indicatesthat said address related to said read request is an address completingan alternate-address process.